AT Command Reference Manual for the RC96ATi and RC144ATi Modem Families
(Preliminary)

This document is provided electronically for use for the express purpose of assisting software developers and end users answer frequently asked questions about Rockwell modem products. This manual ONLY describes the GENERIC Rockwell AT command set. Modem vendors often change, add, and delete commands based on their particular product and feature set. Thus this document does not necessarily describe the AT commands used within your modem, even if it is based on Rockwell chipset products. Always consult your modem vendor's documentation first.

Rockwell International
Digital Communications Division

©1994 Rockwell International Order No. 891
All Rights Reserved March 4, 1994
Printed in U.S.A.

NOTICE

Information furnished by Rockwell International Corporation is believed to be accurate and reliable. However, no responsibility is assumed by Rockwell International for its use, nor any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent rights of Rockwell International other than for circuitry embodied in Rockwell products. Rockwell International reserves the right to change circuitry at any time without notice. This document is subject to change without notice.

Hayes is a registered trademark of Hayes Microcomputer Products, Inc.

1. INTRODUCTION

1.1. OVERVIEW

This manual describes the AT commands for the RC96ATi and RC144ATi modem families:

The descriptions apply to all these modems with any differences between modem product families noted.

1.1.1. Command Syntax

The fundamental DTE interface command syntax is described in Section 2.

1.1.2. Command Descriptions

These commands are grouped into the following categories:

AT commands Section 3
S-Registers Section 4
Fax Class 1 commands Section 5

The AT commands are implemented in microcontroller (MCU) firmware for specific modem models. The support for a command category is identified by modem model in the modem designer's guide. Additional configuration and implementation information is available in release notes and/or readme files that accompany MCU firmware release.

1.2. REFERENCE DOCUMENTATION

Order No. Description
MD95 RC96ATi and RC144ATi Modem Data Sheet
1031 RC96ATi and RC144ATi Modem Designer's Guide

2. COMMAND SYNTAX

2.1. DTE/DCE INTERCHANGE CIRCUITS

Communication between the DTE and modem is half duplex (i.e., only one entity 'talks' at a time).

2.2. COMMAND SYNTAX AND GUIDELINES

2.2.1. DTE Commands

The ISO 646 character set (CCITT T.50 International Alphabet 5, American Standard Code for Information Interchange) is used for the issuance of commands and responses. Only the low-order 7 bits of each character are used for commands or parameters; the high-order bit is ignored. Upper case characters are equivalent to lower case characters.

2.2.2. DTE Command Lines

A command line is a string of characters sent from a DTE to the DCE while the DCE is in a command state. Command lines have a prefix, a body, and a terminator. The prefix consists of the ASCII characters ÒATÓ (065, 084) or ÒatÓ (097, 116). The body is a string of commands restricted to printable ASCII characters (032 - 126). Space characters (ASCII 032) and control characters other than carriage return <CR> (default value = ASCII 013 = 0Dh, see register S3), backspace <BS> (default value = ASCII 008 = 08h, see register S5), and cancel <cntrl-x> (ASCII 024 = 18h) in the command string are ignored. The default terminator is the <CR> character. Characters that precede the AT prefix are ignored.

2.3. AT COMMAND GUIDELINES

Modem operation is controlled by generic AT commands. These AT commands may be basic AT (i.e., commands preceded by AT, AT&, AT%, or AT\), S-Register (e.g., S6=n), or Fax class 1 (e.g., +FTM) commands. The command syntax and operation guidelines governing each of these command categories are described in subsequent sections.

2.3.1. Basic Command Syntax

Characters within the command line are parsed as commands with associated parameter values. The basic commands consist of single ASCII characters, or single characters preceded by a prefix character, followed by a decimal parameter (e.g., Ò&D1"). Missing decimal parameters are evaluated as 0.

2.3.2. Extended Command Syntax

The facsimile commands use extended syntax. They are preceded by the Ò+FÓ characters, and they are terminated by the semicolon Ò:Ó character (ASCII 059) or by the <CR> that terminates the command line.

3. AT COMMAND SET

3.1. AT COMMAND GUIDELINES

The basic AT commands used to control modem operation are defined in this section. These commands are summarized in Appendix A. All these commands may not be available in a specific product depending upon supported data rates and modes. The default values are typical of a fully configured modem supporting all data rates and options. The actual default value is dependent upon modem firmware as defined by the firmware release notes.

3.1.1. AT Commands, DTE Adaption

Under AT operation, the serial interfaced modem performs an autobaud/autoparity/autolength function on each AT header entered. The autolength/autoparity facility can detect 7- or 8-bit characters of even, odd, or no parity with one stop bit. This is not necessary for the parallel interfaced modem since it has direct access to the UART registers.

3.1.2. AT Command Format

Each command line (with the exception of the A/ command) must begin with the character sequence AT and must be terminated by a carriage return. The command line interpretation begins upon receipt of the carriage return character.

The modem supports the editing of command lines by recognizing a backspace character. When modem echo is enabled, the modem responds to receipt of a backspace or delete by echoing a backspace character, a space character, and another backspace. The hex value to be used for the backspace character is programmable through register S5. Values equal to 0 or greater than 127, or the value which corresponds to the carriage return character, cannot be used for the backspace character. This editing is not applicable to the AT header of a command. A command line may be aborted at any time by entering < cntrl-x > (18h).

The AT sequence may be followed by any number of commands in sequence, except for commands such as Z, D, or A. Commands following commands Z, D, or A on the same command line will be ignored. The maximum number of characters on any command line is 39 (including "A" and "T"). If a syntax error is found anywhere in a command line command, the remainder of the line will be ignored and the ERROR result code will be returned.

Most commands entered with parameters out of range will not be accepted and the ERROR response will be returned to the DTE.

Commands will only be accepted by the modem once the previous command has been fully executed, which is normally indicated by the return of an appropriate result code. Execution of commands D and A, either as a result of a direct command or a re-execute command, will be aborted if another character is entered before completion of the handshake.

3.1.3. Escape Code Sequence

When the modem has established a connection and has entered on-line data mode, it is possible to break into the data transmission in order to issue further commands to the modem in an on-line command mode. This is achieved by the DTE sending to the modem a sequence of three ASCII characters specified by register S2. The default character is '+'. The timing of the three characters must comply with specific time constraints. There is a guard time before the first character (the pre-sequence time), a guard time following the third character (the post-sequence time), and a guard time-out between the first and second characters and between the second and third characters (the inter-character time). These times are controlled by the value recorded in register S12.

3.2. AT COMMAND SET

The modem will respond to the commands detailed below. Parameters applicable to each command are listed with the command description. The defaults shown for each configuration command are those used in the Rockwell factory profileÊ0.

3.2.1. AT Commands

A/ - Re-execute Command

The modem behaves as though the last command line had been re-sent by the DTE. "A/" will repeat all the commands in the command buffer.

The principal application of this command is to place another call (using the Dial command) that failed to connect due to a busy line, no answer, or a wrong number. This command must appear alone on a command line. This command should not be terminated by a carriage return.

AT= x - Write to Selected S-Register

This command writes the value x to the currently selected S-Register. An S-Register can be selected by using the ATSn command. All of the S-Registers will return the OK response if x is a number.

Result Codes

OK For all arguments.

AT? - Read Selected S-Register

This command reads and displays the selected S-Register. An S-Register can be selected by using the ATSn command.

Result Codes:

OK For all arguments.

A - Answer

The modem will go off-hook and attempt to answer an incoming call if correct conditions are met. Upon successful completion of answer handshake, the modem will go on-line in answer mode. Operation is also dependent upon +FCLASS command.

If +FCLASS=0 is selected, the modem will enter the connect state after exchanging carrier with the remote modem. If no carrieris detected within a period specified in register S7, the modem hangs up. Any character entered during the connect sequence will abort the connection attempt.

If +FCLASS=1 is selected, the modem will go off-hook in V.21 answer mode. It will generate the V.21 2100 Hz answer tone for 3 ± 0.5 seconds and, following a delay of 70 ms, will proceed as if the +FTH=3 command were issued. At any stage up to (but excluding) the +FTH=3 command state, any character will abort the communication. (See the description of the +FTH command for details.)

Bn - CCITT or Bell

When the modem is configured to allow either option, the modem will select Bell or CCITT modulation for a line speed connection of 300 or 1200 bps according to the parameter supplied. Any other line speed will use a CCITT modulation standard. The parameter value, if valid, is written to S27 bit 6. (Also, see ATFn command.)

B0 Selects CCITT operation at 300 or 1200 bps during Call Establishment and a subsequent connection.

B1 Selects BELL operation at 300 or 1200 bps during Call Establishment and a subsequent connection. (Default.)

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

Cn - Carrier Control

This command is included for compatibility only, and has no effect other than returning a result code. The only valid parameter is 1.

Result Codes:

OK n = 1.

ERROR Otherwise.

Dn - Dial

This command directs the modem to go on-line, dial according to the string entered and attempt to establish a connection. If no dial string is supplied, the modem will go on-line and attempt the handshake in originate mode. NOTE: If the ATD command is issued before the S1 register has cleared, the modem will respond with the NO CARRIER result code.

If +FCLASS=0, the modem will behave as a data modem and will attempt to connect to another data modem. The modem will have up to the period of time specified by register S6 or S7 to wait for carrier and complete the handshake. If this time expires before the modem can complete the handshake, the modem will go on-hook with the NO CARRIER response. This command will be aborted in progress upon receipt of any DTE character before completion of the handshake.

If +FCLASS=1, the modem will behave as a facsimile modem and attempt to connect to a facsimile machine (or modem) by entering the HDLC V.21 channel 2 receive state (as if +FRH=3 had been issued). This command will be aborted upon receipt of any DTE character if the modem has not finished dialing. In this case, the modem will go on-hook and return to command mode after displaying the NO CARRIER message. If the modem has finished dialing, it proceeds as if the +FRH=3 command has been issued. (Refer to the +FRH command to determine how the modem behaves following this stage.)

Dial Modifiers. The valid dial string parameters are described below. Punctuation characters may be used for clarity, with parentheses, hyphen, and spaces being ignored.

0-9 DTMF digits 0 to 9.

* The 'star' digit (tone dialing only).

# The 'gate' digit (tone dialing only).

A-D DTMF digits A, B, C, and D.

L Re-dial last number: the modem will re-dial the last valid telephone number. The L must be immediately after the D with all the following characters ignored).

P Select pulse dialing: pulse dial the numbers that follow until a "T" is encountered. Affects current and subsequent dialing.

T Select tone dialing: tone dial the numbers that follow until a "P" is encountered. Affects current and subsequent dialing. Some countries prevent changing dialing modes after the first digit is dialed.

R This command will be accepted, but not acted on.

S=n Dial the number stored in the directory (n = 0 to 3). (See &Zn.)

! Flash: the modem will go on-hook for a time defined by the value of S29.

W Wait for dial tone: the modem will wait for dial tone before dialing the digits following "W". If dial tone is not detected within the time specified by S7, the modem will abort the rest of the sequence, return on-hook, and generate an error message.

@ Wait for silence: the modem will wait for at least 5 seconds of silence in the call progress frequency band before continuing with the next dial string parameter. If the modem does not detect these 5 seconds of silence before the expiration of the call abort timer (S7), the modem will terminate the call attempt with a NO ANSWER message. If busy detection is enabled, the modem may terminate the call with the BUSY result code. If answer tone arrives during execution of this parameter, the modem handshakes.

& Wait for AT&T "bong" tone for credit card dialing before continuing with the dial string. If bong is not detected within the time specified by S7, the modem will abort the rest of the sequence, return on-hook, and generate an error message.

, Dial pause: the modem will pause for a time specified by S8 before dialing the digits following ",".

; Return to command state. Added to the end of a dial string, this causes the modem to return to the command state after it processes the portion of the dial string preceding the ";". This allows the user to issue additional AT commands while remaining off-hook. The additional AT commands may be placed in the original command line following the ";" and/or may be entered on subsequent command lines. The modem will enter call progress only after an additional dial command is issued without the ";" terminator. Use "H" to abort the dial in progress, and go back on-hook.

^ Toggles calling tone enable/disable: applicable to current dial attempt only.

( ) Ignored: may be used to format the dial string.

- Ignored: may be used to format the dial string.

< space> Ignored: may be used to format the dial string.

< i> Invalid character: will be ignored.

En - Command Echo

The modem enables or disables the echo of characters to the DTE according to the parameter supplied. The parameter value, if valid, is written to S14 bit 1.

E0 Disables command echo.

E1 Enables command echo. (Default.)

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

Fn - Select Line Modulation

This command selects the line modulation according to the parameter supplied. The line modulation is fixed unless Automode is selected. This command interacts with the S37 and the N command. The parameter value, if valid, is written to S37 bits 0-4. To select line modulation, it is recommended that either the F command, or a combination of the S37 and the N command, be used, but not both.

F0 Selects auto-detect mode. Sets N1 and sets S31 bit 1. In this mode, the modem configures for Automode operation. All connect speeds supported by the modem are possible according to the remote modem's preference. The contents of S37 are ignored as is the sensed DTE speed.

F1 Selects V.21 or Bell 103 according to the B setting as the only acceptable line speed resulting in a subsequent connection. Sets N0, sets S37 to 1, and clears S31 bit 1. This command is equivalent to the command string: ATN0S37=1.

F2 Not supported.

F3 Selects V.23 as the only acceptable line modulation for a subsequent connection. Originator is at 75 bps and answerer is at 1200 bps. Sets N0, sets S37 to 7, and clears S31 bit 1. This command is equivalent to the command string: ATN0S37=7.

F4 Selects V.22 1200 or Bell 212A according to the B command setting as the only acceptable line speed for a subsequent connection. Sets N0, sets S37 to 5, and clears S31 bit 1. This command is equivalent to the command string: ATN0S37=5.

F5 Selects V.22 bis as the only acceptable line modulation for a subsequent connection. Sets N0, sets S37 to 6, and clears S31 bit 1. This command is equivalent to the command string: ATN0S37=6.

F6 Select V.32 bis 4800 or V.32 4800 as the only acceptable line modulation for a subsequent connection. Sets N0, sets S37 to 8, and clears S31 bit 1. This command is equivalent to the command string: ATN0S37=8.

F7 Selects V.32 bis 7200 as the only acceptable line modulation for a subsequent connection. Sets N0, sets S37 to 12, and clearsS31 bit 1. This command is equivalent to the command string: ATN0S37=12.

This setting also allows connection at the Rockwell proprietary 7200 V.32 speed, e.g., with a RC9696/12 based modem.

F8 Selects V.32 bis 9600 or V.32 9600 as the only acceptable line modulations for a subsequent connection. Sets N0, sets S37 to 9, and clears S31 bit 1. This command is equivalent to the command string: ATN0S37=9.

F9 Selects V.32 bis 12000 as the only acceptable line modulation for a subsequent connection. Sets N0, sets S37 to 10, and clears S31 bit 1. This command is equivalent to the command string: ATN0S37=10.

This setting also allows connection at the Rockwell proprietary 12000 V.32 speed, e.g., with a RC9696/12 based modem.

F10 Selects V.32 bis 14400 as the only acceptable line modulation for a subsequent connection. Sets N0, sets S37 to 11, and clears S31 bit 1. This command is equivalent to the command string: ATN0S37=11.

Hn - Disconnect (Hang-Up)

This command initiates a hang up sequence.

H0 The modem will release the line if the modem is currently on-line, and will terminate any test (AT&T) that is in progress.

H1 If on-hook, the modem will go off-hook and enter command mode.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

In - Identification

The modem reports to the DTE the requested result according to the command parameter.

I0 Reports product code (e.g., "14400").

I1 Reports a precomputed checksum (see firmware release notes).

I2 Reports "OK".

I3 Reports firmware revision (VX.XXX)-model code (A = 64K US, C = 128K US), interface type (S = serial; P = parallel), and MCU model (39 = C39) (e.g., "V1.297-CS29").

I4 Reports OEM defined identifier string (e.g., "RC96ATi") in either Hayes-compatible binary format.

I5 Reports Country Code parameter (e.g., "022").

I6 Reports modem data pump model and internal code revision (e.g, RC144DPi Rev CE).

Result Codes:

OK n = 0 to 6.

ERROR Otherwise.

Ln - Speaker Volume

The modem sets the speaker volume control according to the parameter supplied. The parameter value, if valid, is written to S22 bits 0 and 1.

L0 Low volume.

L1 Low volume. (Default.)

L2 Medium volume.

L3 High volume.

Result Codes:

OK n = 0 to 3.

ERROR Otherwise.

Mn - Speaker Control

This command selects when the speaker will be on or off. The parameter value, if valid, is written to S22 bits 2 and 3.

M0 Speaker is always off.

M1 Speaker is on during call establishment, but off when receiving carrier. (Default.)

M2 Speaker is always on.

M3 Speaker is off when receiving carrier and during dialing, but on during answering.

Result Codes:

OK n = 0 to 3.

ERROR Otherwise.

Nn - Automode Enable

This command enables or disables Automode detection. The parameter value, if valid, is written to S31 bit 1.

N0 Automode detection is disabled. A subsequent handshake will be conducted according to the contents of S37 or, if S37 is zero, according to the most recently sensed DTE speed.

N1 Automode detection is enabled. A subsequent handshake will be conducted according to the Automode algorithm supported by the modem. This command is equivalent to F0. (Default.)

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

On - Return to On-Line Data Mode

This command determines how the modem will enter the on-line data mode. If the modem is in the on-line command mode, the enters the on-line data mode with or without a retrain. If the modem is in the off-line command mode (no connection), ERROR is reported.

O0 Enters on-line data mode without a retrain. Handling is determined by the Call Establishment task. Generally, if a connection exists, this command connects the DTE back to the remote modem after an escape (+++).

O1 Enters on-line data mode with a retrain before returning to on-line data mode.

Result Codes:

OK n = 0 or 1 and a connection exists.

ERROR Otherwise or if not connected.

P - Set Pulse Dial Default

This command forces pulse dialing until the next T dial modifier or T command is received. Sets S14 bit 5.

As soon as a dial command is executed which explicitly specifies the dialing mode for that particular call (e.g., ATDT...), this command is overridden so that all future dialing will be tone dialed. (See T command.)

Result Code:

OK

Qn - Quiet Results Codes Control

The command enables or disables the sending of result codes to the DTE according to the parameter supplied. The parameter value, if valid, is written to S14 bit 2.

Q0 Enables result codes to the DTE. (Default.)

Q1 Disables result codes to the DTE.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

Sn - Read/Write S-Register

The modem selects an S-Register, performs an S-Register read or write function, or reports the value of an S-Register.

n Establishes S-Register n as the last register accessed.

n=v Sets S-Register n to the value v.

n? Reports the value of S-Register n.

The parameter n can be omitted, in which case the last S-Register accessed will be assumed. The S can be omitted for AT= and AT?, in which case the last S-Register accessed will be assumed.

For example:

ATS7 establishes S7 as the last accessed register.

AT=40 sets the contents of the last register accessed to 40.

ATS=20 sets the contents of the last register accessed to 20.

If the number "n" is beyond the range of the S-Registers available, the modem will return the ERROR message. The value "v" is "MOD"ed with 256. If the result is outside the range permitted for a given S-Register the values will still be stored, but functionally the lower and higher limits will be observed. Input and output are always in decimal format. Note that some S-Registers are read-only.

In some cases, writing to the S-Register will appear to be accepted but the value will not actually be written.

T - Set Tone Dial Default

This command forces DTMF dialing until the next P dial modifier or P command is received. The modem will set an S-Register bit to indicate that all subsequent dialing should be conducted in tone mode. Note that the DP command will override this command. Clears S14 bit 5.

Result Code:

OK

Vn - Result Code Form

This command selects the sending of short-form or long-form result codes to the DTE. The parameter, if valid, is written to S14 bit 3.

V0 Enables short-form (terse) result codes. Line feed is not issued before a short-form result code.

V1 Enables long-form (verbose) result codes. (Default.)

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

Wn - Connect Message Control.

This command controls the format of CONNECT messages. The parameter value, if valid, is written to S31 bits 2 and 3. Note that the Wn command can be overridden by register S95 bits (see S95 description).

W0 Upon connection, the modem reports only the DTE speed (e.g., CONNECT 19200). Subsequent responses are disabled. (Default.)

W1 Upon connection, the modem reports the line speed, PROTOCOL NONE, and the DTE speed, respectively. Subsequent responses are disabled.

W2 Upon connection, the modem reports the DCE speed (e.g., CONNECT 14400). Subsequent responses are disabled.

Result Codes:

OK n = 0, 1, or 2.

ERROR Otherwise.

Xn - Extended Result Codes

This command selects which subset of the result messages will be used by the modem to inform the DTE of the results of commands.

If the user wishes to enforce dial tone detection, a "W" can be placed in the dial string (see D command). Note that the information below is based upon the default implementation of the X results table. Table 3-1 indicates the messages which are enabled for each X value.

If the modem is in facsimile mode (+FCLASS=1), the only message sent to indicate a connection is CONNECT without a speed indication.

X0 Disables monitoring of busy tones; send only OK, CONNECT, RING, NO CARRIER, ERROR, and NO ANSWER result codes. If busy tone detection is enforced and busy tone is detected, NO CARRIER will be reported. If dial tone detection is enforced or selected and dial tone is not detected, NO CARRIER will be reported instead of NO DIAL TONE. The value 000b is written to S22 bits 6, 5, and 4, respectively.

X1 Disables monitoring of busy tones; send only OK, CONNECT, RING, NO CARRIER, ERROR, NO ANSWER, and CONNECT XXXX (XXXX = rate). Blind dialing enabled/disabled by country parameters. If busy tone detection is enforced and busy tone is detected, NO CARRIER will be reported instead of BUSY. If dial tone detection is enforced or selected and dial tone is not detected, NO CARRIER will be reported instead of NO DIAL TONE. The value 100b is written to S22 bits 6, 5, and 4, respectively.

X2 Disables monitoring of busy tones; send only OK, CONNECT, RING, NO CARRIER, ERROR, NO DIALTONE, NO ANSWER, and CONNECT XXXX. If busy tone detection is enforced and busy tone is detected, NO CARRIER will be reported instead of BUSY. If dial tone detection is enforced or selected and dial tone is not detected, NO DIAL TONE will be reported instead of NO CARRIER. The value 101b is written to S22 bits 6, 5, and 4, respectively.

X3 Enables monitoring of busy tones; send only OK, CONNECT, RING, NO CARRIER, ERROR, NO ANSWER, and CONNECT XXXX. If dial tone detection is enforced and dial tone is not detected, NO CARRIER will be reported. The value 110b is written to S22 bits 6, 5, and 4, respectively.

X4 Enables monitoring of busy tones; send all messages. The value 111b is written to S22 bits 6, 5, and 4, respectively. (Default.)

Result Codes:

OK n = 0 to 4.

ERROR Otherwise.

Table 3-1. Result Codes

Short Form Long Form n Value in ATXn Command
0 1 2 3 4            
0 OK x x x x x
1 CONNECT x x x x x
2 RING x x x x x
3 NO CARRIER x x x x x
4 ERROR x x x x x
5 CONNECT 1200 1 x x x x
6 NO DIALTONE 3 3 x x x
7 BUSY 3 3 3 x x
8 NO ANSWER x x x x x
9 CONNECT 0600 1 x x x x
10 CONNECT 2400 1 x x x x
11 CONNECT 4800 1 x x x x
12 CONNECT 9600 1 x x x x
13 CONNECT 7200 1 x x x x
14 CONNECT 12000 1 x x x x
15 CONNECT 14400 1 x x x x
16 CONNECT 19200 1 x x x x
17 CONNECT 38400 1 x x x x
18 CONNECT 57600 1 x x x x
22 CONNECT 75TX/1200RX 1 x x x x
23 CONNECT 1200TX/75RX 1 x x x x
33 FAX x x x x x
35 DATA x x x x x
40 CARRIER 300 x x x x x
44 CARRIER 1200/75 x x x x x
45 CARRIER 75/1200 x x x x x
46 CARRIER 1200 x x x x x
47 CARRIER 2400 x x x x x
48 CARRIER 4800 x x x x x
49 CARRIER 7200 x x x x x
50 CARRIER 9600 x x x x x
51 CARRIER 12000 x x x x x
52 CARRIER 14400 x x x x x
+F4 +FCERROR x x x x x
Note: An 'X' in a column indicates that the message (either the long form if verbose, or the value only for short form) will be generated when that particular value of 'n' (shown at the top of the column) has been selected by the use of ATXn. If the column is blank, then no message will be generated for that X option. A numeral indicates which less explicit message (verbose or short form) will be output for that X option.
(Also, see Section 3.3).

Yn - Long Space Disconnect

This command enables/disables the generation and response to long space disconnect. The parameter value, if valid, is written to S21 bit 7.

Y0 Disables long space disconnect. (default.)

Y1 Enables long space disconnect. The modem will send a long space of four seconds prior to going on-hook.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

Zn - Soft Reset and Restore Profile

The modem performs a soft reset and restores (recalls) the configuration profile according to the parameter supplied. If no parameter is specified, zero is assumed.

Z0 Soft reset and restore stored profile 0.

Z1 Soft reset and restore stored profile 1.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

3.2.2. AT& Commands

& Cn - RLSD (DCD) Option

The modem controls the RLSD output in accordance with the parameter supplied. The parameter value, if valid, is written to S21 bit 5.

& C0 RLSD remains ON at all times. (Default.)

& C1 RLSD follows the state of the carrier.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

& Dn - DTR Option

This command interprets the ON to OFF transition of the DTR signal from the DTE in accordance with the parameter supplied. The parameter value, if valid, is written to S21 bits 3 and 4.

& D0 - DTR drop is interpreted according to the current &Q setting as follows: (Default.)

& Q0, &Q6 DTR is ignored (assumed ON). Allows operation with DTEs which don't provide DTR.

& Q1 DTR drop causes the modem to hang up. Auto-answer is not affected.

& Q2, &Q3 DTR drop causes the modem to hang up. Auto-answer is inhibited.

& D1 DTR drop is interpreted according to the current &Q setting as follows:

& Q0, &Q1, &Q6 DTR drop is interpreted by the modem as if the asynchronous escape sequence had been entered. The modem returns to asynchronous command state without disconnecting.

& Q2, &Q3 DTR drop causes the modem to hang up. Auto-answer is inhibited.

& D2 DTR drop is interpreted according to the current &Q setting as follows:

& Q0, &Q1, &Q6 DTR drop causes the modem to hang up. Auto-answer is inhibited.

& D3 DTR drop is interpreted according to the current &Q setting as follows:

& Q0, &Q1, &Q6 DTR drop causes the modem to perform a soft reset as if the Z command were received. The &Y setting determines which profile is loaded.

& Q2, &Q3 DTR drop causes the modem to hang up. Auto-answer is inhibited.

If &Q6 or +FCLASS=1 is in effect, the action taken is the same as for &Q0.

& Fn - Restore Factory Configuration (Profile)

The modem loads the factory default configuration (profile). The factory defaults are identified for each command and in the S-Register descriptions. A configuration (profile) consists of a subset of S-Registers.

& F0 Restore factory configuration 0.

& F1 Restore factory configuration 1.

Result Codes:

OK

ERROR If the modem is connected.

& Gn - Select Guard Tone

The modem generates the guard tone selected by this command according to the parameter supplied (DPSK modulation modes only). The parameter value, if valid, is written to S23 bits 6 and 7.

& G0 Disables guard tone. (Default.)

& G1 Disables guard tone.

& G2 Selects 1800 Hz guard tone.

Result Codes:

OK n = 0 to 2.

ERROR Otherwise.

& Jn - Telephone Jack Control

This command is only included for compatibility and performs no function except to load the S-Register. The parameter value, if valid, is written S21 bit 1.

& J0 &J0 command. (Default.)

& J1 &J1 command.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

& Kn - Flow Control

This command defines the DTE/DCE (terminal/modem) flow control mechanism. The parameter value, if valid, is written to S39 bits 0, 1, and 2.

& K0 Disables flow control.

& K3 Enables RTS/CTS flow control. (Default for data modem modes.)

& K4 Enables XON/XOFF flow control.

& K5 Enables transparent XON/XOFF flow control.

& K6 Enables both RTS/CTS and XON/XOFF flow control. (Default for fax modem modes.)

Result Codes:

OK n = 0, 3, 4, 5, or 6.

ERROR Otherwise.

& Ln - Leased Line Command

This command requests leased or dial-up line operation. This command is provided for compatibility only; no mode change is performed, dial-up operation continues. The OK response is returned for a valid parameter, but no other action is performed. The parameter value, if valid, is written to S27 bit 2.

& L0 Requests dial-up operation. Dial-up operation continues.

& L1 Requests leased line operation. Dial-up operation continues.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

& Mn - Asynchronous/Synchronous Mode Selection

This command determines the DTR operating mode. The modem treats the &M command as a subset of the &Q command.

& M0 Selects direct asynchronous operation. Note that the command sequence &M0\N0 selects normal buffered mode, but the command sequence \N0&M0 selects direct mode. This is because the \N0 command is analogous to the &Q6 command. The value 000b is written to S27 bits 3, 1, and 0, respectively. (See &Q).

& M1 Selects synchronous connect mode with async off-line command mode. The value 001b is written to S27 bits 3, 1, and 0, respectively. (Serial interface operation only.)

& M2 Selects synchronous connect mode with async off-line command mode. Same as &M1 except that &M2 enables DTR dialing of directory slot 0. The modem will disconnect if DTR is OFF for more than the period in S25 (in units of hundredths of a second): the data connection will be synchronous. The value 010b is written to S27 bits 3, 1, and 0, respectively. (Serial interface operation only.)

& M3 Selects synchronous connect mode. This mode allows DTR to act as a talk/data switch. The call is manually initiated while DTR is inactive. When DTR becomes active, the handshake proceeds in originate or answer mode according to S14 bit 7. The value 011b is written to S27 bits 3, 1, and 0, respectively. (Serial interface operation only.)

Result Codes:

OK n = 0 to 3.

ERROR Otherwise.

& Pn - Select Pulse Dial Make/Break Ratio

This command determines the make/break ratio used during pulse dialing. The parameter value, if valid, is written to S28 bits 3 and 4.

& P0 Selects 39%-61% make/break ratio at 10 pulses per second. (Default.)

& P1 Selects 33%-67% make/break ratio at 10 pulses per second.

Result Codes:

OK n = 0 to 3.

ERROR Otherwise.

& Qn - Sync/Async Mode

This command is an extension of the &M command and is used to control the connection modes permitted. It is used in conjunction with S36 and S48. (Also, see \N.)

NOTE: When the &Q0 to &Q3 command is issued to select the mode, the subsequent connect message will report the DCE speed regardless of the W command and S95 settings.

& Q0 Selects direct asynchronous operation. The value 000b is written to S27 bits 3, 1, and 0, respectively. See &M0.

& Q1 Selects synchronous connect mode with async off-line command mode. The value 001b is written to S27 bits 3, 1, and 0, respectively. See &M1. (Serial interface operation only.)

& Q2 Selects synchronous connect mode with async off-line command modeand enables DTR dialing of directory 0. The value 010b is written to S27 bits 3, 1, and 0, respectively. See &M2. (Serial interface operation only.)

& Q3 Selects synchronous connect mode with async off-line command mode and enables DTR to act as Talk/Data switch. The value 011b is written to S27 bits 3, 1, and 0, respectively. See &M3. (Serial interface operation only.)

& Q4 Reserved.

& Q5 Reserved.

& Q6 Selects asynchronous operation in normal mode (speed buffering). The value 110b is written to S27 bits 3, 1, and 0, respectively.

Result Codes:

OK n = 0 to 6.

ERROR Otherwise.

& Rn - RTS/CTS Option

This selects how the modem controls CTS. CTS operation is modified if hardware flow control is selected (see &K command). The parameter value, if valid, is written to S21 bit 2.

& R0 In sync mode, CTS tracks the state of RTS; the RTS-to-CTS delay is defined by S26.

& R1 In sync mode, CTS is always ON (RTS transitions are ignored). In async mode, CTS will only drop if required by flow control. (Default.)

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

& Sn - DSR Override

This command selects how the modem will control DSR. The parameter value, if valid, is written to S21 bit 6.

& S0 DSR will remain ON at all times. (Default.)

& S1 DSR will become active after answer tone has been detected and inactive after the carrier has been lost.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

& Tn - Test and Diagnostics

The modem will perform selected test and diagnostic functions according to the parameter supplied. A test can be run only when in an asynchronous operation in non-error-correction mode (normal or direct mode). To terminate a test in progress, the escape sequence must be entered first, except for parameters 7 and 8 (see Section 3.1.3). If S18 is non-zero, a test will terminate automatically after the time specified by S18 and display the OK message.

& T0 Terminates test in progress. Clears S16.

& T1 Initiates local analog loopback, V.54 Loop 3. Sets S16 bit 0. If a connection exists when this command is issued, the modem hangs up. The CONNECT XXXX message is displayed upon the start of the test.

& T2 Returns ERROR.

& T3 Initiates local digital loopback, V.54 Loop 2. Sets S16 bit 2. If no connection exists, ERROR is returned. Sets S16 bit 4 when the test is in progress.

& T4 Enables digital loopback acknowledgment for remote request, i.e., an RDL request from a remote modem is allowed. Sets S23 bit 0. (Default.)

& T5 Disables digital loopback acknowledgment for remote request, i.e., an RDL request from a remote modem is denied. Clears S23 bit 0.

& T6 Requests a remote digital loopback (RDL), V.54 Loop 2, without self test. If no connection exists, ERROR is returned. Sets S16 bit 4 when the test is in progress. The CONNECT XXXX message is displayed upon the start of the test.

& T7 Requests a remote digital loopback (RDL),V.54 Loop 2, with self test. (In self test, a test pattern is looped back and checked by the modem.) If no connection exists, ERROR is returned. When the test is terminated either via expiration of S18, or via the &T0 or H command, the number of detected errors is reported to the DTE. Sets S16 bit 5 when the test is in progress.

& T8 Initiates local analog loopback, V.54 Loop 3, with self test. (In self test, a test pattern is looped back and checked by the modem.) If a connection exists, the modem hangs up before the test is initiated. When the test is terminated either via expiration of S18, or via the &T0 or H command, the number of detected errors is reported to the DTE. Sets S16 bit 6 when the test is in progress.

& V - Display Current Configuration and Stored Profiles

Reports the current (active) configuration, the stored (user) profiles, and the first four stored telephone numbers. The stored profiles and telephone numbers are not displayed if the NVRAM is not installed or is not operational as detected by the NVRAM test during reset processing.

Result Code:

OK

Example: AT&V

ACTIVE PROFILE:
B0 E1 L1 M1 N1 QO T V1 W0 X4 Y0 &C0 &D0 &G2 &J0 &K3 &Q5 &R1 &S0 &T4 &X0 &Y0
S00:002 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002 S07:030 S08:002 S09:006
S10:014 S11:255 S12:050 S18:000 S25:005 S26:001 S36:007 S37:000 S38:020 S44:020 S46:138
S48:007 S95:000
STORED PROFILE 0:
B0 E1 L1 M1 N1 QO T V1 W0 X4 Y0 &C0 &D0 &G2 &J0 &K3 &Q5 &R1 &S0 &T4 &X0
S00:002 S02:043 S06:002 S07:030 S08:002 S09:006 S10:014 S11:095 S12:050 S18:000
S36:007 S37:000 S40:105 S41:003 S44:020 S46:138 S95:000
STORED PROFILE 1:
B0 E1 L1 M1 N1 QO T V1 W0 X4 Y0 &C0 &D0 &G2 &J0 &K3 &Q5 &R1 &S0 &T4 &X0
S00:002 S02:043 S06:002 S07:030 S08:002 S09:006 S10:014 S11:095 S12:050 S18:000
S36:007 S37:000 S40:105 S41:003 S44:020 S46:138 S95:000
TELEPHONE NUMBERS:
0 = 1 =
2 = 3 =
OK

If the NVRAM is not installed or is not operational as detected by the NVRAM test, the following message is displayed:

NVRAM FAILED OR NOT INSTALLED

&Wn - Store Current Configuration

Saves the current (active) configuration (profile), including S-Registers, in one of the two user profiles in NVRAM as denoted by the parameter value. This command will yield an ERROR message if the NVRAM is not installed or is not operational as detected by the NVRAM test.

The current configuration is comprised of a list of storable parameters illustrated in the &V command. These settings are restored to the active configuration upon receiving an Zn command or at power up (see &Yn command).

& W0 Store the current configuration as profile 0.

& W1 Store the current configuration as profile 1.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

& Xn - Select Synchronous Clock Source

Selects the source of the transmit clock for the synchronous mode of operation. The parameter value, if valid, is written to S27 bits 4 and 5.

In asynchronous mode, the transmit and receive clocks are turned OFF. In synchronous mode, the clocks are turned ON with the frequency of 1200 Hz or faster corresponding to the speed that is selected for modem operation.

& X0 Selects internal timing. The modem generates the transmit clock signal and applies it to the TXCLK output at the serial interface.

& X1 Selects external timing. The local DTE sources the transmit clock signal on the XTCLK input of the serial interface. The modem applies this clock to the TXCLK output at the serial interface.

& X2 Selects slave receive timing. The modem derives the transmit clock signal from the incoming carrier and applies it to the TXCLK output at the serial interface.

Result Codes:

OK n = 0 to 2.

ERROR Otherwise.

& Yn - Designate a Default Reset Profile

Selects which user profile will be used after a hard reset.

& Y0 The modem will use profile 0.

& Y1 The modem will use profile 1.

Result Codes:

n = 0 to 1.

ERROR If n > 1, or if NVRAM is not installed or is not operational.

& Zn=x - Store Telephone Number

The modem can store up to four telephone numbers and each telephone number dial string can contain up to 35 digits.

& Zn=x n = 0 to 3 and x = dial string. (Requires 256-byte NVRAM.)

Result Codes:

OK For n ∑ 3 and x ∑ 35 digits.

ERROR If n > 3 or x > 35 digits, or if NVRAM is not installed or is not operational.

3.2.3. AT% Commands

%En - Enable/Disable Line Quality Monitor and Auto-Retrain or Fallback/Fall Forward

Controls whether or not the modem will automatically monitor the line quality and request a retrain (%E1) or fall back when line quality is insufficient or fall forward when line quality is sufficient (%E2). Applies to dial-up line only. The parameter value, if valid, is written to S41 bits 2 and 6.

If enabled, the modem attempts to retrain for a maximum of 30 seconds.

%E0 Disable line quality monitor and auto-retrain. (Default.)

%E1 Enable line quality monitor and auto-retrain.

%E2 Enable line quality monitor and fallback/fall forward.

Result Codes:

OK n = 0, 1, or 2.

ERROR Otherwise.

Fallback/Fall Forward. When %E2 is active, the modem monitors the line quality (EQM). When line quality is insufficient, the modem will initiate a rate renegotiation to a lower speed within the V.32 bis/V.32 modulation speeds. The modem will keep falling back if necessary until the speed reaches 4800 bps. Below this rate, the modem will only do retrains if EQM thresholds are exceeded. If the EQM is sufficient for at least one minute, the modem will initiate a rate renegotiation to a higher speed within the V.32/V.32bis modulation speeds. The rate renegotiations will be done without a retrain if a V.32bis connection is established.

Speeds attempted during fallback/fall forward are those shown to be available in the rate sequences exchanged during the initial connection. Fallback/fall forward is available in error correction and normal modes, but not in direct mode or synchronous mode with external clocks.

%L - Line Signal Level

Returns a value which indicates the received signal level. The value returned is a direct indication (DAA dependent) of the receive level at the MDP, not at the telephone line connector. For example, 009 = -9 dBm, 043 = -43 dBm, and so on.

Result Codes:

OK

%Q - Line Signal Quality

Reports the line signal quality (DAA dependent). Returns the higher order byte of the EQM value. Based on the EQM value, retrain or fallback/fall forward may be initiated if enabled by %E1 or %E2.

Example: AT%Q

015Result Codes:

OK If connected.

ERROR If not connected, or connected in 300 bps, V.23, or fax modes.

3.2.4. AT\ Commands

\Gn - Modem-to-Modem Flow Control (XON/XOFF)

The modem enables or disables the generation or recognition of modem-to-modem XON/XOFF flow control according to the parameter supplied. The parameter value, if valid, is written to S41 bit 3.

Due to the buffering system used in the modem, modem-to-modem flow control is normally disabled.

\G0 Disables modem-to-modem XON/XOFF flow control. (Default.)

\G1 Enables modem-to-modem XON/XOFF flow control.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

\Kn - Break Control

Controls the response of the modem to a break received from the DTE or the remote modem according to the parameter supplied. The parameter value, if valid, is written to S40 bits 3, 4, and 5.

The response is different in three separate states.

The first state is where the a break is sent to the modem from the DTE when the modem is operating in data transfer mode:

\K0 Enter on-line command mode, no break sent to the remote modem.

\K1 Clear data buffers and send break to remote modem.

\K2 Same as 0.

\K3 Send break to remote modem immediately.

\K4 Same as 0.

\K5 Send break to remote modem in sequence with transmitted data. (Default.)

The second case is where a break is sent to the remote modem when the modem is in the on-line command state (waiting for AT commands) during a data connection:

\K0 Clear data buffers and send break to remote modem.

\K1 Clear data buffers and send break to remote modem. (Same as 0.)

\K2 Send break to remote modem immediately.

\K3 Send break to remote modem immediately. (Same as 2.)

\K4 Send break to remote modem in sequence with data.

\K5 Send break to remote modem in sequence with data. (Same as 4.) (Default.)

The third case is where a break is received from a remote modem:

\K0 Clears data buffers and sends break to the DTE.

\K1 Clears data buffers and sends break to the DTE. (Same as 0.)

\K2 Send a break immediately to DTE.

\K3 Send a break immediately to DTE. (Same as 2.)

\K4 Send a break in sequence with received data to DTE.

\K5 Send a break in sequence with received data to DTE. (Same as 4.) (Default.)

Result Codes:

OK n = 0 to 5.

ERROR Otherwise.

\Nn - Operating Mode

This command controls the preferred mode to be negotiated in a subsequent data connection. This command is affected by the OEM firmware configuration.

\N0 Selects normal speed buffered mode. (Forces &Q6.)

\N1 Serial interface selected - Selects direct mode and is equivalent to &M0, &Q0 mode of operation. (Forces &Q0.)

Parallel interface selected - Same as \N0.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

3.2.5. AT+ Commands

+Hn - Enable/Disable RPI and DTE Speed

This command enables or disables Rockwell Protocol Interface (RPI) processing and sets the DTE speed.

+H0 Disable RPI

+H1 Enable RPI and set DTE speed to 19200 bps

+H2 Enable RPI and set DTE speed to 38400 bps

+H3 Enable RPI and set DTE speed to 57600 bps

Result Codes:

OK n = 0 to 3.

ERROR Otherwise.

3.3. AT COMMAND RESULT CODES

The modem responds to commands from the DTE and to activity on the line by signalling to the DTE in the form of result codes. The result codes that the modem can send are described below.

Two forms of each result code are available: long-form, an English-like "verbose" response, and short-form, a data-like numeric response (included in parentheses following the long-form). The long-form code is preceded and terminated by the sequence < CR> < LF>. The short-form is terminated by < CR>, only with no preceding sequence.

If result messages are suppressed, nothing is returned to the DTE.

00- OK

The OK code is returned by the modem to acknowledge execution of a command line.

01- CONNECT

The modem will send this result code upon connecting when:

1. The line speed is 300 bps and the modem has been instructed to report the line speed to the DTE upon connecting, or

2. The DTE speed is 300 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting, or

3. The range of result code responses is restricted by the X command such that no speed reporting is allowed.

02- RING

The modem sends this result code when incoming ringing is detected on the line.

03- NO CARRIER

The modem sends this result code when attempting to establish a call if:

1. Ringback is detected and later ceases but no carrier is detected within the period of time determined by register S7, or

2. No ringback is detected within the period of time determined by register S7.

This result code is also used when the modem auto-disconnects due to loss of carrier.

Under X0, if busy tone detection is enforced, this result code is used as a response to the detection of busy or circuit busy. Under X0, if dial tone detection is enforced or selected, this result code is used to indicate that dial tone has not been detected.

04- ERROR

The modem returns this result code if the command line contains a syntax error or it is unable to execute a command contained in the command line. It is issued if a command does not exist or if the parameter supplied is outside the permitted range.

05- CONNECT 1200

For X1, X2, X3, and X4, the modem sends this result code when:

1. The line speed is 1200 bps and the modem has been instructed to report the line speed to the DTE upon connecting, or

2. The DTE speed is 1200 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.

(Also, see the W command.)

06- NO DIALTONE

For X2 and X4, the modem sends this result code if it has been instructed to wait for dial tone during dialing but none is received.

07- BUSY

For X3 and X4, if busy tone detection is enforced, the modem sends this result code when attempting to originate a call if the busy (engaged) signal is detected on the line.

08- NO ANSWER

The modem sends this result code when attempting to originate a call if a continuous ringback signal is detected on the line until the expiration of the timer S7.

09- CONNECT 0600

For X1, X2, X3, and X4, the modem sends this result code when:

1. The line speed is 600 bps and the modem has been instructed to report the line speed to the DTE upon connecting, or

2. The DTE speed is 600 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.

10- CONNECT 2400

For X1, X2, X3, and X4, the modem sends this result code when:

1. The line speed is 2400 bps and the modem has been instructed to report the line speed to the DTE upon connecting, or

2. The DTE speed is 2400 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.

11- CONNECT 4800

For X1, X2, X3, and X4, the modem sends this result code when the DTE speed is 4800 bps and the modem has been instructed to report the DTE speed upon connecting.

12- CONNECT 9600

For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 9600 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.

13- CONNECT 7200

For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 7200 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.

14- CONNECT 12000

For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 12000 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.

15- CONNECT 14400

For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 14400 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.

16- CONNECT 19200

For X1, X2, X3, and X4, the modem returns this result code upon connecting when the DTE speed is 19,200 bps and the modem has been instructed to report the DTE speed upon connecting.

17- CONNECT 38400

For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 38400 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.

18- CONNECT 57600

For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 57600 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.

22- CONNECT 75TX/1200RX

For X1, X2, X3, and X4, the modem returns this result code upon establishing a V.23 originate connection when the modem has been instructed to report the DCE speed upon connection.

23- CONNECT 1200TX/75RX

For X1, X2, X3, and X4, the modem returns this result code upon establishing a V.23 answer connection when the modem has been instructed to report the DCE speed upon connection.

33- FAX

The modem returns this result code when a fax modem connection is established in a facsimile mode.

35- DATA

The modem returns this result code when a data modem connection is established in a facsimile mode.

40- CARRIER 300

The modem returns this result code when either a V.21 or Bell 103 carrier has been detected on the line and carrier reporting has been enabled. (See S95 and Xn.)

44- CARRIER 1200/75

The modem sends this result code when the V.23 backward channel carrier has been detected on the line and carrier reporting has been enabled. (See S95 and Xn.)

45- CARRIER 75/1200

The modem sends this result code when the V.23 forward channel carrier has been detected on the line and carrier reporting has been enabled. (See S95 and Xn.)

46- CARRIER 1200

The modem sends this result code when either the high or low channel carrier in either V.22 or Bell 212 mode has been detected on the line and carrier reporting has been enabled. (See S95 and Xn.)

47- CARRIER 2400

The modem sends this result code when either the high or low channel carrier in V.22 bis mode has been detected on the line, and carrier reporting has been enabled. (See S95 and Xn.)

48- CARRIER 4800

The modem sends this result code when the 4800 bps data rate in V.32 bis or V.32 mode has been detected on the line, and carrier reporting has been enabled. (See S95 and Xn.)

49- CARRIER 7200

The modem sends this result code when the 7200 bps data rate in V.32 bis mode has been detected on the line, and carrier reporting has been enabled. (See S95 and Xn.)

50- CARRIER 9600

The modem sends this result code when the 9600 bps data rate in V.32 bis or V.32 mode has been detected on the line, and carrier reporting has been enabled. (See S95 and Xn.)

51- CARRIER 12000

The modem sends this result code when the 12000 bps data rate in V.32 bis mode has been detected on the line, and carrier reporting has been enabled. (See S95 and Xn.)

52- CARRIER 14400

The modem sends this result code when the 14400 bps data rate in V.32 bis mode has been detected on the line, and carrier reporting has been enabled. (See S95 and Xn.)

70- PROTOCOL: NONE

This message is sent to the DTE when the modem has connected without any form of error correction, and the PROTOCOL message reporting has been enabled. (See S95 and Xn.)

+F4- +FCERROR

This message is sent to the DTE when high speed fax data (V.27, V.29, V.33, or V.17) is expected and a V.21 signal is received.

4. S-REGISTERS

The S-Registers are summarized in Table 4-1 along with their default values. Registers denoted with an '*' in Table 4-1 may be stored in one of the two user profiles by entering the &Wn command. One of these profiles may be loaded at any time by using the Zn command. Registers or register fields quoted as ÒreservedÓ are reserved for current or future use by the firmware.

All bit-mapped registers are read-only. The appropriate AT command which controls the relevant bits in the S-Register should be used to change the value.

4.1. FACTORY DEFAULTS

The factory default values are stored in ROM and are loaded into the active configuration at power up or by the ATZn command. In addition, the designated default profile is subsequently loaded, and may change some of the factory default values. The designated default profile can be changed by entering the &Yn command where n is one of the two possible user profiles.

The defaults shown are those used by Rockwell in factory profiles zero and one.

The default values shown in Table 4-1 may vary by modem firmware configuration. Consult the MCU firmware release notes for exact configuration.

The factory default values may be loaded at any time by entering the &Fn command.

Table 4-1. S-Register Summary
Register Function Range Units Save Default
S0 Rings to Auto-Answer 0-255 rings * 0
S1 Ring Counter 0-255 rings   0
S2 Escape Character 0-255 ASCII * 43
S3 Carriage Return Character 0-127 ASCII   13
S4 Line Feed Character 0-127 ASCII   10
S5 Backspace Character 0-255 ASCII   8
S6 Wait Time for Dial Tone 2-255 s * 2
S7 Wait Time for Carrier 1-255 s * 50
S8 Pause Time for Dial Delay Modifier 0-255 s * 2
S9 Carrier Detect Response Time 1-255 0.1 s * 6
S10 Carrier Loss Disconnect Time 1-255 0.1 s * 14
S11 DTMF Tone Duration 50-255 0.001 s * 95
S12 Escape Code Guard Time 0-255 0.02 s * 50
S13 Reserved - -   -
S14 General Bit Mapped Options Status - - * 138 (8Ah)
S15 Reserved - -   -
S16 Test Mode Bit Mapped
Options Status ( &T)
- -   0
S17 Reserved - -   -
S18 Test Timer 0-255 s * 0
S19-S20 Reserved - -   -
S21 V.24/General Bit Mapped Options Status - - * 4 (04h)
S22 Speaker/Results Bit Mapped Options Status - - * 117 (75h)
S23 General Bit Mapped Options Status   - * 55 (37h)
S24 Sleep Inactivity Timer 0-255 s * 0
S25 Delay to DTR Off 0-255 s or
0.01 s
  5
S26 RTS-to-CTS Delay 0-255 0.01 s   1
S27 General Bit Mapped Options Status - - * 73 (49h)
S28 General Bit-Mapped Options Status - - * 0
S29 Flash Dial Modifier Time 0-255 10 ms   0
S30 Disconnect Inactivity Timer 0-255 10 s   0
S31 General Bit-Mapped Options Status - - * 2
S32 XON Character 0-255 ASCII   17 (11h)
S33 XOFF Character 0-255 ASCII   19 (13h)
S34-S36 Reserved - -   -
S37 Line Connection Speed - - * 0
S38 Reserved - -   -
S39 Flow Control Bit Mapped Options Status - - * 3
S40 General Bit-Mapped Options Status - - * 105 (69h)
S41 General Bit-Mapped Options Status - - * 3
S42-S45 Reserved - -   -
S91 PSTN Transmit Attenuation Level 0-15 dBm   10
S92 Fax Transmit Attenuation Level 0-15 dBm   10
S95 Result Code Messages Control - - * 0

* Register value may be stored in one of two user profiles with the &W command.

4.2. S-REGISTER DEFINITIONS

S0 - Number of Rings to Auto-Answer

Sets the number of the rings required before the modem automatically answers a call. Setting this register to zero disables auto-answer mode.

Range: 0-255 rings

Default: 0

S1 - Ring Counter

S1 is incremented each time the modem detects a ring signal on the telephone line. S1 is cleared if no rings occur over an eight second interval.

Range: 0-255 rings

Default: 0

S2 - Escape Character

S2 holds the decimal value of the ASCII character used as the escape character. The default value corresponds to an ASCII '+'. A value over 127 disables the escape process, i.e., no escape character will be recognized.

Range: 0-255, ASCII decimal

Default: 43 (+)

S3 - Carriage Return Character

Sets the command line and result code terminator character. Pertains to asynchronous operation only.

Range: 0-127, ASCII decimal

Default: 13 (Carriage Return)

S4 - Line Feed Character

Sets the character recognized as a line feed. Pertains to asynchronous operation only. The Line Feed control character is output after the Carriage Return control character if verbose result codes are used

Range: 0-127, ASCII decimal

Default: 10 (Line Feed)

S5 - Backspace Character

Sets the character recognized as a backspace. Pertains to asynchronous operation only. The modem will not recognize the Backspace character if it is set to a value that is greater than 32 ASCII. This character can be used to edit a command line. When the echo command is enabled, the modem echoes back to the local DTE the Backspace character, an ASCII space character and a second Backspace character; this means a total of three characters are transmitted each time the modem processes the Backspace character.

Range: 0-32, ASCII decimal

Default: 8 (Backspace)

S6 - Wait Time for Dial Tone Before Blind Dialing

Sets the length of time, in seconds, that the modem will wait before starting to dial after going off-hook when blind dialing. The ÒWait for Dial ToneÓ call progress feature (W dial modifier in the dial string) will override the value in register S6.

The modem always pauses for a minimum of 2 seconds, even if the value of S6 is less than 2 seconds.

Range: 2-255 seconds

Default: 2

S7 - Wait Time For Dial Tone After ÒWÓ Dial Modifier

Sets the length of time, in seconds, that the modem will wait for dial tone when encountering a ÒWÓ dial modifier before continuing with the next dial string parameter.

Range: 1-255 seconds

Default: 50

S8 - Pause Time For Dial Delay

Sets the time, in seconds, that the modem must pause when the Ò,Ó dial modifier is encountered in the dial string.

Range: 0-255 seconds

Default: 2

S9 - Carrier Detect Response Time

Sets the time, in tenths of a second, that the carrier must be present before the modem considers it valid and turns on RLSD. As this time is increased, there is less chance to detect a false carrier due to noise from the telephone line.

Range: 1-255 tenths of a second

Default: 6 (0.6 second)

S10 - Lost Carrier To Hang Up Delay

Sets the length of time, in tenths of a second, that the modem waits before hanging up after a loss of carrier. This allows for a temporary carrier loss without causing the local modem to disconnect. When register S10 is set to 255, the modem functions as if a carrier is always present.

The actual interval the modem waits before disconnecting is the value in register S10 minus the value in register S9. Therefore, the S10 value must be greater than the S9 value or else the modem disconnects before it recognizes the carrier.

Range: 1-255 tenths of a second

Default: 14 (1.4 seconds)

S11 - DTMF Tone Duration

Sets the duration of tones in DTMF dialing. This value has no effect on pulse dialing.

Range: 50-255 milliseconds

Default: 95 (95 milliseconds)

S12 - Escape Code Guard Time

Defines the maximum period, in fiftieths of a second, allowed between consecutive asynchronous escape characters (+) for the escape sequence to be considered valid.

Range: 0-255 1/50 of a second

Default: 50 (1 second)

S13 - Reserved

S14 - General Bit Mapped Options Status

Indicates the status of command options.

Default: 138 (8Ah) (10001010b)

Bit 0 Ñ This bit is ignored.

Bit 1 Ñ Command echo (En)

0 = Disabled (E0)

1 = Enabled (E1) (Default.)

Bit 2 Ñ Quiet mode (Qn)

0 = Send result codes (Q0) (Default.)

1 = Do not send result codes (Q1)

Bit 3 Ñ Result codes (Vn)

0 = Numeric (V0)

1 = Verbose (V1) (Default.)

Bit 4 Ñ Reserved

Bit 5 Ñ Tone (T)/Pulse (P)

0 = Tone (T) (Default.)

1 = Pulse (P)

Bit 6 Ñ Reserved

Bit 7 Ñ Originate/Answer

0 = Answer

1 = Originate (Default.)

S15 - Reserved

S16 - General Bit Mapped Test Options Status

Indicates the test in progress status.

Default: 0

Bit 0 Ñ Local analog loopback

0 = Disabled (Default.)

1 = Enabled (&T1)

Bit 1 Ñ Not used

Bit 2 Ñ Local digital loopback

0 = Disabled (Default.)

1 = Enabled (&T3)

Bit 3 Ñ Remote digital loopback (RDL) status

0 = Modem not in RDL (Default.)

1 = RDL in progress

Bit 4 Ñ RDL requested (AT&T6)

0 = RDL not requested (Default.)

1 = RDL requested (&T6)

Bit 5 Ñ RDL with self test

0 = Disabled (Default.)

1 = Enabled (&T7)

Bit 6 Ñ Local analog loopback (LAL) with self test

0 = Disabled (Default.)

1 = Enabled (&T8)

Bit 7 Ñ Not used

S17 - Reserved

S18 - Test Timer

Sets the length of time, in seconds, that the modem conducts a test (commanded by &Tn) before returning to the command mode. If this register value is zero, the test will not automatically terminate; the test must be terminated from the command mode by issuing an &T0 or H command. When S18 is non-zero, the modem returns the OK message upon test termination.

Range: 0-255 seconds

Default: 0

S19-S20 - Reserved

S21 - V.24/General Bit Mapped Options Status

Indicates the status of command options.

Default: 4 (00000100b)

Bit 0 Ñ Set by &Jn command but ignored otherwise.

0 = &J0 (Default.)

1 = &J1

Bit 1 Ñ Reserved

Bit 2 Ñ CTS behavior (&Rn)

0 = CTS tracks RTS (&R0)

1 = CTS always on (&R1) (Default.)

Bit 3,4 Ñ DTR behavior (&Dn)

0 = &D0 selected (Default.)

1 = &D1 selected

2 = &D2 selected

3 = &D3 selected

Bit 5 Ñ RLSD (DCD) behavior (&Cn)

0 = &C0 selected (Default.)

1 = &C1 selected

Bit 6 Ñ DSR behavior (&Sn)

0 = &S0 selected (Default.)

1 = &S1 selected

Bit 7 Ñ Long space disconnect (Yn)

0 = Y0 (Default.)

1 = Y1

S22 - Speaker/Results Bit Mapped Options Status

Indicates the status of command options.

Default: 117 (75h) (01110101b)

Bit 0,1 Ñ Speaker volume (Ln)

0 = Off (L0)

1 = Low (L1) (Default.)

2 = Medium (L2)

3 = High (L3)

Bit 2,3 Ñ Speaker control (Mn)

0 = Disabled (M0)

1 = Off on carrier (M1) (Default.)

2 = Always on (M2)

3 = On during handshake (M3)

Bit 4,5,6 Ñ Limit result codes (Xn)

0 = X0

4 = X1

5 = X2

6 = X3

7 = X4 (Default.)

Bit 7Ñ Reserved

S23 - General Bit Mapped Options Status

Indicates the status of command options.

Default: 55 (37h) (00110111b)

Bit 0Ñ Grant RDL

0 = RDL not allowed (&T5)

1 = RDL allowed (&T4) (Default.)

Bit 1,2,3 Ñ DTE Rate

0 = 0 - 300 bps

1 = 600 bps

2 = 1200 bps

3 = 2400 bps (Default.)

4 = 4800 bps

5 = 9600 bps

6 = 19200 bps

7 = 38400 bps or higher

Bit 4,5 Ñ Assumed DTE parity

0 = even

1 = not used

2 = odd

3 = none (Default.)

Bit 6,7 Ñ Guard tone (&Gn)

0 = None (&G0) (Default.)

1 = None (&G1)

2 = 1800 Hz (&G2)

S24 - Sleep Inactivity Timer

Sets the length of time, in seconds, that the modem will operate in normal mode with no detected telephone line or DTE line activity before entering low-power sleep mode. The timer is reset upon any DTE line or telephone line activity. If the S24 value is zero, neither DTE line nor telephone inactivity will cause the modem to enter the sleep mode.

Range: 0-255 seconds

Default: 0

S25 - Delay To DTR

Sets the length of time that the modem will ignore DTR for taking the action specified by &Dn. Its units are seconds for synchronous modes and one hundredths of a second for other modes.

Range: 0-255 (1 second for synchronous modes 1; 0.01 second otherwise )

Default: 5

S26 - RTS to CTS Delay

Sets the time delay, in hundredths of a second, before the modem turns CTS ON after detecting an OFF-to-ON transition on RTS when &R0 is commanded. Pertains to synchronous operation only.

Range: 0-255 hundredths of a second

Default: 1

S27 - Bit Mapped Options Status

Indicates the status of command options.

Default: 74 (4Ah) (01001010b) (Default.)

Bit 0,1,3 Ñ Synchronous/asynchronous selection (&Mn/&Qn)

3 1 0

0 0 0 = &M0 or &Q0

0 0 1 = &M1 or &Q1

0 1 0 = &M2 or &Q2

0 1 1 = &M3 or &Q3

1 0 0 = Reserved

1 0 1 = Reserved

1 1 0 = &Q6 (Default.)

Bit 2 Ñ Leased line command (&Ln)

0 = Dial up line requested (&L0) (Default.)

1 = Leased line requested (&L1)

Bit 4,5 Ñ Internal clock select (&Xn)

0 = Internal clock (&X0) (Default.)

1 = External clock (&X1)

2 = Slave clock (&X2)

Bit 6 Ñ CCITT/Bell mode select (Bn)

0 = CCITT mode (B0)

1 = Bell mode (B1) (Default.)

Bit 7 - Reserved

S28 - Bit Mapped Options Status

Default: 0

Bit 0-1 Ñ Reserved

Bit 2 Ñ Reserved (always 0).

Bit 3,4 Ñ Pulse dialing (&Pn)

0 = 39%-61% make/break ratio at 10 pulses per second (&P0) (Default.)

1 = 33%-67% make/break ratio at 10 pulses per second (&P1)

Bit 5-7 Ñ Reserved

S29 - Flash Dial Modifier Time

Sets the length of time, in units of 10 ms, that the modem will go on-hook when it encounters the flash (!) dial modifier in the dial string.

Range: 0-255 10 ms intervals

Default: 0 (disabled)

S30 - Disconnect Inactivity Timer

Sets the length of time, in tens of seconds, that the modem will stay online before disconnecting when no data is sent or received. Any data transmitted will reset the timer. The timer is inoperative in synchronous mode.

Range: 0-255 tens of seconds (0-2550 seconds)

Default: 0 (disabled)

S31 - Bit Mapped Options Status

Default: 2 (00000010b)

Bit 0 Ñ Reserved

Bit 1 Ñ Automode detection enable/disable (Nn)

0 = Disabled (N0)

1 = Enabled (N1) (Default.)

Bit 2,3 Ñ Connect message control (Wn)

0 = DTE speed only (W0) (Default.)

1 = Full reporting (W1)

2 = DCE speed only (W2)

Bit 3 Ñ Reserved

Bit 4-7 Ñ Reserved

S32 - XON Character

Sets the value of the XON character.

Range: 0-255, ASCII decimal

Default: 17 (11h)

S33 - XOFF Character

Sets the value of the XOFF character.

Range: 0-255, ASCII decimal

Default: 19 (13h)

S34-S36 - Reserved

S37 - Desired Line Connection Speed

Default: 0

Bit 0-3 Ñ Desired line connection speed. This is interlinked with the Fn command. If an invalid number is entered, the number is accepted into the register, but S37 will act as if the default value has been entered.

0 = Attempt auto mode connection (F0). (Default)

1-3 = Attempt to connect at 300 bps (F1).

4 = Reserved.

5 = Attempt to connect at V.22 1200 bps (F4).

6 = Attempt to connect at V.22 bis 2400 bps (F5).

7 = Attempt to connect at V.23 (F3).

8 = Attempt to connect at V.32 bis/V.32 4800 bps (F6).

9 = Attempt to connect at V.32 bis/V.32 9600 bps (F8).

10 = Attempt to connect at V.32 bis 12000 bps (F9).

11 = Attempt to connect at V.32 bis 14400 bps (F10).

12 = Attempt to connect at V.32 bis 7200 bps (F7).

13-15 = Reserved

Bit 4-7 Ñ Reserved

S38 - Reserved

S39 - Flow Control Bit Mapped Options Status

Default: 3 (00000011b)

Bits 0-2 Ñ Status of command options

0 = No flow control

3 = RTS/CTS (&K3) (Default.)

4 = XON/XOFF (&K4)

5 = Transparent XON (&K5)

6 = Both methods (&K6)

Bits 3-7 Ñ Reserved

S40 - General Bit Mapped Options Status

Indicates the status of command options.

Default: 105 (69h) (01101001b)

Bit 0 - 2Ñ Reserved

Bits 3-5 Ñ Break Handling (\Kn)

0 = \K0

1 = \K1

2 = \K2

3 = \K3

4 = \K4

5 = \K5 (Default.)

Bits 6-7 Ñ Reserved

S41 - General Bit Mapped Options Status

Indicates the status of command options.

Default: 131 (10000011b)

Bits 0 -1 Ñ Reserved

Bit 2, 6Ñ Auto retrain and fallback/fall forward (%En)

Bit 6 Bit 2

0 0 = Retrain and fallback/fall forward disabled (%E0) (Default.)

0 1 = Retrain enabled (%E1)

1 0 = Fallback/fall forward enabled (%E2)

Bit 3 Ñ Modem-to-modem flow control

0 = Disabled (\G0) (Default.)

1 = Enabled (\G1)

Bit 4-5, 7 Ñ Reserved

S91 - PSTN Transmit Attenuation Level

Sets the transmit attenuation level from 0 to 15 dBm for the PSTN mode, resulting in a transmit level from 0 to -15ÊdBm.

Range: 0 to 15 dBm (Corresponding to 0 to -15 dBm transmit level.)

Default: 10 (-10 dBm transmit level.)

S92 - Fax Transmit Attenuation Level

Sets the transmit attenuation level from 0 to 15 dBm for the fax mode, resulting in a transmit level from 0 to -15ÊdBm.

Range: 0 to 15 dBm (Corresponding to 0 to -15 dBm transmit level.)

Default: 10 (-10 dBm transmit level.)

S95 - Extended Result Codes

The bits in this register can be set to override some of the Wn command options. A bit set to a 1 in this register will enable the corresponding result code regardless of the Wn setting. Also, refer to Table 3-1.

Default: 0

Bit 0 = CONNECT result code indicates DCE speed instead of DTE speed.

Bit 1= Reserved.

Bit 2 = Enable CARRIER XXXX result code (XXXX = rate; see Table 3-1).

Bit 3 = Enable PROTOCOL XXXX result code (XXXX = protocol identifier; see Table 3-1).

Bit 4 -7= Reserved.

5. FAX CLASS 1 COMMANDS

5.1. FAX I/O PROCESSING

The fax I/O interface supports asynchronous serial and parallel interfaces. The interface rate is 19200 bps. The character format is 8 bits data, no parity, and 1 stop bit. Start and stop elements are removed from the transmit data and added to the receive data. Both transmit and receive data are buffered. Flow control using XON/XOFF (DC1/DC3) or RTS/CTS is provided.

Unique control character strings are identified, filtered, or reinserted into the I/O data stream. These control characters and their resultant action are described below.

5.1.1. DTE-to-Modem Transmit Data Stream

Characters Detected Action Taken

< DLE><data> Delete <DLE><data> characters.

< DLE><ETX> Recognize as a string terminator and take appropriate action.

< DLE><DLE> Replace with single <DLE> character.

5.1.2. Modem-to-DTE Receive Data Stream

Characters Detected Action Taken

< DLE> Insert extra <DLE> ahead of <DLE>.

The modem also identifies the end of a frame by inserting <DLE><ETX> into the data stream after the FCS bytes.

5.1.3. Fax Mode Selection

Fax class 1 commands are identified in Table 5-1. Fax modes and rates are determined by the AT+F commands as described in Section 5.2.

Table 5-1. Fax Class 1 Commands

Command Function
Service Class ID  
+FCLASS= Service Class
Fax Class 1 Commands  
+FAE=n Data/Fax Auto Answer
+FTS=n Stop Transmission and Wait
+FRS=n Receive Silence
+FTM=n Transmit Data
+FRM=n Receive Data
+FTH=n Transmit Data with HDLC Framing
+FRH=n Receive Data with HDLC Framing

5.1.4. Fax Origination

Origination of fax calls is made using the ATD command. Upon completion of the dial function, a calling tone at 1100 Hz is transmitted, with a cadence of 0.5 seconds on and 3 seconds off. The modem automatically enters mode +FRH=3 and sends the CONNECT message to the DTE when FSK flags are detected from the remote.

5.1.5. Fax Answering

Answering of fax calls is identical to answering of data calls with the exception that the modem enters the fax handshaking mode instead of the data handshaking mode after going off-hook. If +FAE=0, the modem, after sending answer tone, automatically enters fax mode (+FTH=3), sends the CONNECT message to the DTE, and starts sending FSK flags. If +FAE=1, the modem determines whether the caller is a data modem or fax modem and sends the DATA or FAX result code, respectively, to the DTE.

5.1.6. Fax Control Transmission

Fax control transmission is initiated by the +FTH=n command. After this command is issued, the modem generates the CONNECT message and transmits carrier in the modulation scheme specified by the parameter n. The modem then transmits HDLC flags for a minimum of 1 second. The modem continues to transmit the HDLC flags until it receives a character from the DTE.

When characters are received from the DTE, the modem adds start and end flags, performs zero-bit insertion, generates FCS, and deletes <DLE><chr> character pairs before transmitting the characters to the remote fax machine. Each <DLE><DLE> sequence is transmitted as a single <DLE>. <DLE><ETX> is considered as the end of frame marker and is not transmitted. All data received from the DTE after <DLE><ETX> is ignored by the modem until the modem generates either the CONNECT, OK, or ERROR result code.

If no more data is in the transmit buffer and the final bit was a 1 (bit 4 of the second byte received from the DTE), the modem generates the OK result code and returns to the command mode. If the final bit was a 0, the modem generates the CONNECT message and waits for further data from the DTE while transmitting HDLC flags. If no more data is received before 5 seconds elapse, the modem drops carrier, goes on-hook, and generates the ERROR result code.

5.1.7. Fax Control Reception

Fax control reception is initiated using the AT+FRH=n command. After this command is issued, the modem looks for carrier in the modulation scheme specified by the parameter n. If no carrier is detected before the period of time specified by register S7 expires, the modem generates the NO CARRIER message and returns to command mode. If carrier is detected that is not the one specified by the parameter n, the modem generates the +FCERROR message and returns to the command mode. If the specified carrier is detected, the modem generates the CONNECT message and enters the HDLC receive mode.

In HDLC receive mode, the modem receives HDLC frames from the remote fax machine, strips the flags, performs zero-bit deletion, performs error checking, and handles <DLE><chr> character pairs before passing the data to the DTE. The modem prefixes each <DLE> character with another <DLE> character before sending it to the DTE. After the last byte in the frame, the modem sends <DLE><ETX> to the DTE marking the end of the frame. The modem then generates either the OK message if no errors were detected or the ERROR message if errors were detected (FCS is incorrect), and returns to command mode.

While in command mode, the modem continues to receive data in the selected modulation scheme, and sends the data after sending the CONNECT message to the DTE when the DTE reissues the +FRH command with the same parameter. If the DTE issues the +FRH command with a different parameter, the modem clears all buffers and proceeds as described previously.

If carrier is lost while in command mode and the DTE reissues the +FRH command with the same parameter, and there is no data in the buffer, the modem sends the ERROR result code to the DTE and returns to the command mode. If there is data in the buffer, the modem sends the next frame of buffered data to the DTE, followed by <DLE><ETX>, and either the ERROR result code if errors were detected or the OK result code if no errors were detected. The modem then returns to command mode.

The modem concludes an error is detected if carrier is lost for any period of time during or before the reception of a frame. If carrier is lost for a time period longer than the time specified by the register S10, the modem finishes delivering the data in the receive buffer (if any) to the DTE, sends <DLE><ETX>, generates the ERROR message, and returns to command mode. All subsequent data received from the remote is discarded.

If the modem detects a frame abort sequence (seven consecutive ones with no zero insertion) while it is waiting for a frame beginning flag (it was receiving HDLC flags), it will wait for the HDLC flags again until either carrier is lost, or the DTE aborts the process by sending an abort character or by dropping DTR with &D2 in effect. If the frame abort sequence is detected while the modem is receiving a frame it finishes delivering the data in the receive buffer (if any) to the DTE, sends <DLE><ETX>, generates the ERROR message, and returns to command mode. The modem keeps looking for HDLC flags followed by more data from the remote, with the selected modulation scheme.

If the modem detects a receive buffer overflow condition, it concludes that there was an FCS error in that frame. The modem will receive more frames only if a starting flag is detected and there is room in the receive buffer. If a starting flag is detected and there is no room in the buffer, the modem discards all data in that frame.

If the modem receives any character from the DTE after the +FRH command (except flow control characters if software flow control is in effect), or if the modem detects a high-to-low transition of the DTR signal while &D1 is in effect, it sends <DLE><ETX> to the DTE, generates OK result code, and returns to command mode. The receive buffer is cleared and all data received from the remote is discarded. If the modem detects a DTR drop while &D2 is in effect, it goes on-hook, sends <DLE><ETX> to the DTE, generates OK result code, and returns to command mode. If the modem detects a DTR drop while &D3 is in effect, the modem performs a warm reset.

5.1.8. Fax Data Transmission

Fax data transmission is initiated by the AT+FTM=n command. After this command is issued, the modem generates the CONNECT message and transmits carrier in the modulation scheme specified by the parameter n. The modem then transmits constant 1 bits for a minimum of one second and continues to transmit constant 1 bits until it receives a character from the DTE.

When data is received from the DTE, the modem deletes start and stop bits and deletes all <DLE><chr> character pairs before transmitting the data to the remote. Each <DLE><DLE> sequence is transmitted as a single <DLE>. <DLE><ETX> is considered as the end of stream marker, and is not transmitted. All data received from the DTE after the <DLE><ETX> is ignored by the modem until the modem generates either the CONNECT, OK, or ERROR result code.

If no more data is in the transmit buffer, and the last transmitted character was not an ASCII NULL, the modem generates the OK result code and returns to the command mode. If the last character transmitted was an ASCII NULL, the modem generates the CONNECT message to the DTE and waits for further data from the DTE while transmitting NULLs to the remote. If more data is received before five seconds elapse, the modem continues to transmit the data as described in the previous paragraph. If five seconds elapse and no data is received from the DTE, the modem drops carrier, goes on-hook, and generates the ERROR result code.

5.1.9. Fax Data Reception

Fax data reception is initiated using the AT+FRM=n command. After this command is issued, the modem looks for carrier in the modulation scheme specified by the parameter n. If no carrier is detected before the period of time specified by register S7 expires, the modem generates the NO CARRIER message and returns to command mode. If a V.21 carrier is detected when a high speed carrier is expected, the modem generates the +FCERROR message and returns to the command mode. If the specified carrier is detected, the modem generates the CONNECT message and enters the data receive mode.

While in data receive mode, the modem receives data from the remote, adds start and stop bits, and handles <DLE><chr> character pairs before passing the data to the DTE. The modem prefixes each <DLE> character with another <DLE> character before sending it to the DTE.

If carrier is lost for a time period longer than the time specified by the register S10, the modem finishes delivering the data in the receive buffer (if any) to the DTE, sends <DLE><ETX>, generates the NO CARRIER result code, and returns to the command mode. All subsequent data received from the remote is discarded.

If the modem detects a receive buffer overflow condition, it stops receiving from the remote until there is room in the receive buffer. The modem informs the DTE of the buffer overflow after it sends to the DTE the last character that was stored in the buffer before the overflow occurred.

If the modem receives any character from the DTE after the +FRM command (except flow control characters if software flow control is in effect), or if the modem detects a high-to-low transition of the DTR signal while &D1 is in effect, it sends <DLE><ETX> to the DTE, generates the OK result code, and returns to command mode. The receive buffer is cleared and all data received from the remote is discarded. If loss of DTR is detected while &D2 is in effect, the modem goes on-hook, sends <DLE><ETX> followed by OK result code to the DTE, and returns to command mode. If the modem detects a DTR drop while &D3 is in effect, the modem performs a warm reset.

5.2. COMMANDS

+FCLASS=n - Select Service Class

+FCLASS=n command sets the active service class.

Parameters: 0-1

Command options:

+FCLASS=0 Select Data Mode (Default.)

+FCLASS=1 Select Facsimile Class 1

+F<command>? - Report Active Configuration

+F<command>? interrogates the modem to determine the active configuration.

Typical responses are:

+FAE? 0 if auto answer is disabled; 1 if auto answer is enabled

+FCLASS? 0 if in data mode; 1 if in fax class 1;

+F<command>=? - Report Operating Capabilities

+F<command>=? can be used to determine the operating capabilities of the modem.

Typical responses are:

+FAE=? 0 or 1

+FCLASS=? 0, or 1

+FTM=? 24, 48, 72, 96 (9600 bps version)

+FRM=? 24, 48, 72, 96 (9600 bps version)

+FTM=? 24, 48, 72, 73, 74, 96, 97, 98, 121, 122, 145, 146 (14400 bps version)

+FRM=? 24, 48, 72, 73, 74, 96, 97, 98, 121, 122, 145, 146 (14400 bps version)

+FAE=n - Data/Fax Auto Answer

+FAE=n allows the DTE to either restrict answering to class 1, or to automatically detect whether the calling station is a fax class 1 modem or data modem, and answer accordingly.

Parameters: n = 0 or 1

Command options:

n = 0 Disable data/fax auto answer mode. The modem answers as a fax modem only. (Default).

n = 1 Enable data/fax auto answer mode. The modem answers as a fax or data modem.

After a data (not fax) connection is acheived (indicated by the DATA result code), the DTE must issue an ATO command to cause the modem to go on-line.

+FTS=n - Stop Transmission and Wait

+FTS=n causes the modem to terminate a transmission and wait for n 10-ms intervals before responding with the OK result code. An ERROR response code results if this command is issued while the modem is on-hook.

+FRS=n - Receive Silence

+FRS=n causes the modem to report back to the DTE with an OK result code after n 10 ms-intervals of silence have been detected on the line. This command is aborted if any character is received from the DTE. The modem discards the aborting character and issues an OK result code. An ERROR response code results if this command is issued while the modem is on-hook.

+FTM=n - Transmit Data

+FTM=n causes the modem to transmit data using the modulation defined below. An ERROR response code results if this command is issued while the modem is on-hook.

Parameters: See Command options

Command options:

+FTM=24 V.27 ter 2400 bps
+FTM=48 V.27 ter 4800 bps
+FTM=72 V.29 7200 bps
+FTM=73 V.17 7200 bps long
+FTM=74 V.17 7200 bps short
+FTM=96 V.29 9600 bps
+FTM=97 V.17 9600 bps long
+FTM=98 V.17 9600 bps short
+FTM=121 V.17 12000 bps long
+FTM=122 V.17 12000 bps short
+FTM=145 V.17 14400 bps long
+FTM=146 V.17 14400 bps short

+FRM=n - Receive Data

+FRM=n causes the modem to enter the receiver mode using the modulation defined below. An ERROR response code results if this command is issued while the modem is on-hook.

Parameters: See Command options

Command options:

+FRM=24 V.27 ter 2400 bps
+FRM=48 V.27 ter 4800 bps
+FRM=72 V.29 7200 bps
+FRM=73 V.17 7200 bps long
+FRM=74 V.17 7200 bps short
+FRM=96 V.29 9600 bps
+FRM=97 V.17 9600 bps long
+FRM=98 V.17 9600 bps short
+FRM=121 V.17 12000 bps long
+FRM=122 V.17 12000 bps short
+FRM=145 V.17 14400 bps long
+FRM=146 V.17 14400 bps short

+FTH=n - Transmit Data with HDLC Framing

+FTH=n causes the modem to transmit data using HDLC protocol and the modulation defined below. An ERROR response code results if this command is issued while the modem is on-hook.

Parameters: See Command options.

Command options:

+FTH=3 V.21 channel 2 300 bps
+FTH=24 V.27 ter 2400 bps
+FTH=48 V.27 ter 4800 bps
+FTH=72 V.29 7200 bps
+FTH=73 V.17 7200 bps long
+FTH=74 V.17 7200 bps short
+FTH=96 V.29 9600 bps
+FTH=97 V.17 9600 bps long
+FTH=98 V.17 9600 bps short
+FTH=121 V.17 12000 bps long
+FTH=122 V.17 12000 bps short
+FTH=145 V.17 14400 bps long
+FTH=146 V.17 14400 bps short

+FRH=n - Receive Data with HDLC Framing

+FRH=n causes the modem to receive frames using HDLC protocol and the modulation defined below. An ERROR response code results if this command is issued while the modem is on-hook.

Parameters: See Command options.

Command options:

+FTH=3 V.21 channel 2 300 bps
+FRH=24 V.27 ter 2400 bps
+FRH=48 V.27 ter 4800 bps
+FRH=72 V.29 7200 bps
+FRH=73 V.17 7200 bps long
+FRH=74 V.17 7200 bps short
+FRH=96 V.29 9600 bps
+FRH=97 V.17 9600 bps long
+FRH=98 V.17 9600 bps short
+FRH=121 V.17 12000 bps long
+FRH=122 V.17 12000 bps short
+FRH=145 V.17 14400 bps long
+FRH=146 V.17 14400 bps short

 

5.3. EXAMPLES

Examples of calling (transmitting) and answering (receiving) one page using fax class 1 commands are shown in Tables 5-2 and 5-3, respectively.

Table 5-2. Fax Class 1 Calling Sequence (One Page)

DTE Commands DCE Responses

(Host) (Modem) Remote Fax Notes

(1) AT+FCLASS=1 (2) OK Set to Class 1

PHASE A

(3) ATDT6163 (4) Dials (5) Answers +FRH=3 implied by Dialing

(6) CONNECT (7) Send HDLC flags

PHASE B

(8) Send NSF frame

(9) <NSF>,OK

(10) AT+FRH=3 (11) CONNECT

(12) Send CSI frame

(13) <CSI>,OK

(14) AT+FRH=3 (15) CONNECT

(16) Send DIS frame Last frame bit = 1

(17) <DIS>,OK (18) Drop carrier

(19) AT+FTH=3 (20) Send HDLC flags (21) Receive flags

(21) CONNECT

(22) <TSI> (23) Send TSI frame (24) Receive TSI Last frame bit = 0

(25) CONNECT

(26) <DCS> (27) Send DCS frame (28) Receive DCS Last frame bit = 1

(29) Detect last frame bit

(39) OK, drop carrier

(31) AT+FTS=8 (32) OK, wait 80 ms

(33) AT+FTM=96 (34) Send V.29

(35) CONNECT

(36) <TCF> (37) Send TCF data (38) Receive & check

(39) OK

(40) AT+FRH=3 (41) CONNECT

(42) Send CFR frame Last frame bit = 1

(43) <CFR>,OK (44) Drop carrier

(45) OK

PHASE C

(46) AT+FTM=96 (47) Send V.29

(48) CONNECT

(49) age data (50) Send page data (51) Receive data

(52) OK

(53) AT+FTH=3 (54) Send HDLC flags (55) Receive flags

(56) CONNECT

PHASE D

(57) <EOP> (58) Send EOP frame (59) Receive EOP Last frame bit = 1

(60) OK, drop carrier

(61) AT+FRH=3 (62) CONNECT

(63) Send MCF frame Last frame bit = 1

(64) <MCF>, OK

(65) AT+FTH=3 (66) Send HDLC flags (67) Receive flags

(68) CONNECT

(69) <DCN> (70) Send DCN frame (71) Receive DCN Last frame bit = 1

(72) OK, drop carrier

PHASE E

(73) ATH0 (74) OK, hang up (75) Hang up

Table 5-3. Fax Class 1 Answering Sequence (One Page)

DTE Commands DCE Responses

(Host) (Modem) Remote Fax Notes

(1) AT+FCLASS=1 (2) OK Set to Class 1

PHASE A

(3) FAX machine dials

(4) RING

(5) ATA (6) Modem answers

(7) Send HDLC flags (8) Receive flags +FTH=3 implied by

answering

(9) CONNECT

PHASE B

(10) <NSF> (11) Send NSF frame (12) Receive NSF Last frame bit = 0

(13) CONNECT

(14) <CSI> (15) Send CSI frame (16) Receive CSI Last frame bit = 0

(17) CONNECT

(18) <DIS> (19) Send DIS frame (20) Receive DIS Last frame bit = 1

(21) OK, drop carrier

(22) AT+FRH=3 (23) CONNECT

(24) Send TSI frame Last frame bit = 0

(25) <TSI>, OK

(26) AT+FRH=3 (27) CONNECT

(28) Send DCS frame Last frame bit = 1

(29) <DCS>, OK (30) Drop Carrier

(31) AT+FRM=96

(32) Send V.29

(33) CONNECT (34) Send TCF frame

(35) <TCF> (36) Drop carrier

(37) NO CARRIER

(38) AT+FTH=3 (39) CONNECT

(40) <CFR> (41) Send CFR frame (42) Receive CFR Last frame bit = 1

(43) OK, drop carrier

PHASE C

(44) AT+FRM=96

(45) Send page data

(46) <page data> (47) Drop carrier

(48) NO CARRIER

PHASE D

(49) AT+FRH=3 (50) CONNECT

(51) Send EOP frame Last frame bit = 1

(52) <EOP>, OK

(53) AT+FTH=3 (54) CONNECT

(55) <MCF> (56) Send MCF frame (57) Receive MCF Last frame bit = 1

(58) OK, drop carrier

(59) AT+FRH=3 (60) CONNECT

(61) Send DCN frame Last frame bit = 1

(62) <DCN>, OK

PHASE E

(73) ATH0 (74) OK, hang up (75) Hang up

A. AT COMMAND SET SUMMARY

A.1. BASIC AT COMMANDS

Command Function

A/ Re-execute command.

A Go off-hook and attempt to answer a call.

B0 Select V.22 connection at 1200 bps.

B1 Select Bell 212A connection at 1200 bps.

C1 Return OK message.

Dn Dial modifier.

E0 Turn off command echo.

E1 Turn on command echo.

F0 Select auto-detect mode (equivalent to N1).

F1 Select V.21 or Bell 103.

F2 Reserved.

F3 Select V.23 line modulation.

F4 Select V.22 or Bell 212A 1200 bps line speed.

F5 Select V.22 bis line modulation.

F6 Select V.32 bis or V.32 4800 line modulation.

F7 Select V.32 bis 7200 line modulation.

F8 Select V.32 bis or V.32 9600 line modulation.

F9 Select V.32 bis 12000 line modulation.

F10 Select V.32 bis 14400 line modulation.

H0 Initiate a hang-up sequence.

H1 If on-hook, go off-hook and enter command mode.

I0 Report product code.

I1 Report pre-computed checksum.

I3 Report firmware revision, model, and interface type.

I4 Report response programmed by an OEM.

I5 Report the country code parameter.

I6 Report modem data pump model.

L0 Set low speaker volume.

L1 Set low speaker volume.

L2 Set medium speaker volume.

L3 Set high speaker volume.

M0 Turn speaker off.

M1 Turn speaker on during handshaking and turn speaker off while receiving carrier.

M2 Turn speaker on during handshaking and while receiving carrier.

M3 Turn speaker off during dialing and receiving carrier and turn speaker on during answering.

N0 Turn off Automode detection.

N1 Turn on Automode detection.

O0 Go on-line.

O1 Go on-line and initiate a retrain sequence.

P Force pulse dialing.

Q0 Allow result codes to DTE.

Q1 Inhibit result codes to DTE.

Sn Select S-Register as default.

Sn? Return the value of S-Register n.

=v Set default S-Register to value v.

? Return the value of default S-Register.

T Force DTMF dialing.

V0 Report short form (terse) result codes.

V1 Report long form (verbose) result codes.

W0 Report DTE speed.

W1 Report line speed, PROTOCOL NONE, and DTE speed.

W2 Report DCE speed.

X0 Report basic call progress result codes, i.e., OK, CONNECT, RING, NO CARRIER (also, for busy, if enabled, and dial tone not detected), NO ANSWER and ERROR.

X1 Report basic call progress result codes and connections speeds (OK, CONNECT, RING, NO CARRIER (also, for busy, if enabled, and dial tone not detected), NO ANSWER, CONNECT XXXX, and ERROR.

X2 Report basic call progress result codes and connections speeds, i.e., OK, CONNECT, RING, NO CARRIER (also, for busy, if enabled, and dial tone not detected), NO ANSWER, CONNECT XXXX, and ERROR.

X3 Report basic call progress result codes and connection rate, i.e., OK, CONNECT, RING, NO CARRIER, NO ANSWER, CONNECT XXXX, BUSY, and ERROR.

X4 Report all call progress result codes and connection rate, i.e., OK, CONNECT, RING, NO CARRIER, NO ANSWER, CONNECT XXXX, BUSY, NO DIAL TONE and ERROR.

Y0 Disable long space disconnect before on-hook.

Y1 Enable long space disconnect before on-hook.

Z0 Restore stored profile 0 after warm reset.

Z1 Restore stored profile 1 after warm reset.

& C0 Force RLSD active regardless of the carrier state.

& C1 Allow RLSD to follow the carrier state.

& D0 Interpret DTR ON-to-OFF transition per &Qn.

& D1 Interpret DTR ON-to-OFF transition per &Qn.

& D2 Interpret DTR ON-to-OFF transition per &Qn.

& D3 Interpret DTR ON-to-OFF transition per &Qn.

& F0 Restore factory configuration 0.

& F1 Restore factory configuration1.

& G0 Disable guard tone.

& G1 Disable guard tone.

& G2 Enable 1800 Hz guard tone.

& J0 Set S-Register response only for compatibility.

& J1 Set S-Register response only for compatibility.

& K0 Disable DTE/DCE flow control.

& K3 Enable RTS/CTS DTE/DCE flow control.

& K4 Enable XON/XOFF DTE/DCE flow control.

& K5 Enables transparent XON/XOFF flow control.

& K6 Enables both RTS/CTS and XON/XOFF flow control.

& M0 Select direct asynchronous mode.

& M1 Select sync connect with async off-line command mode.*

& M2 Select sync connect with async off-line command mode and enable DTR dialing of directory zero.*

& M3 Select sync connect with async off-line command mode and enable DTR to act as Talk/Data switch.*

& P0 Set 10 pps pulse dial with 39%/61% make/break.

& P1 Set 10 pps pulse dial with 33%/67% make/break.

& Q0 Select direct asynchronous mode.

& Q1 Select sync connect with async off-line command mode.*

& Q2 Select sync connect with async off-line command mode and enable DTR dialing of directory zero.*

& Q3 Select sync connect with async off-line command mode and enable DTR to act as Talk/Data switch.*

& Q6 Select asynchronous operation in normal mode.

& R0 CTS tracks RTS (async).

& R1 CTS is always active.

& S0 DSR is always active.

& S1 DSR acts per V.25.

& T0 Terminate any test in progress.

& T1 Initiate local analog loopback.

& T2 Returns ERROR result code.

& T3 Initiate local digital loopback.

& T4 Allow remote digital loopback.

& T5 Disallow remote digital loopback request.

& T6 Request an RDL without self-test.

& T7 Request an RDL with self-test.

& T8 Initiate local analog loop with self-test.

& V Display current configurations.

& W0 Store the active profile in NVRAM profile 0.

& W1 Store the active profile in NVRAM profile 1.

& X0 Select internal timing for the transmit clock.

& X1 Select external timing for the transmit clock.

& X2 Select slave receive timing for the transmit clock.

& Y0 Recall stored profile 0 upon power up.

& Y1 Recall stored profile 1 upon power up.

& Zn=x Store dial string x (to 45) to location n (0 to 3).

%E0 Disable line quality monitor and auto retrain.

%E1 Enable line quality monitor and auto retrain.

%E2 Enable line quality monitor and fallback/fall forward.

%L Return received line signal level.

%Q Report the line signal quality.

\G0 Disable modem to modem flow control.

\G1 Enable modem to modem flow control.

\Kn Controls break handling during three states.

\N0 Select normal speed buffered mode.

A.2. FAX CLASS 1

+FCLASS=n Service class.

+FAE=n Data/fax auto answer

+FRH=n Receive data with HDLC framing.

+FRM=n Receive data.

+FRS=n Receive silence.

+FTH=n Transmit data with HDLC framing.

+FTM=n Transmit data.

+FTS=n Stop transmission and wait.

* Serial interface operation only.

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