U.S. Robotics Modems Die, Zoom's Live In FCC Lightning Test
USR Courier "Pops and Flashes" in Test by Independent Lab CCL

Boston, MA, March 4, 1997 - After FCC Part 68 surge testing conducted by Communication Certification Laboratory (CCL), the low-cost Zoom® V.34X faxmodem emerged fully functional while the U.S. Robotics Courier V.Everything™ external faxmodem failed to operate.

The Part 68 metallic surge test simulates electrical surges that are typical of those caused by lightning striking a telephone line, which transmits the surge to the modem.

The FCC test simulates a lightning strike by exposing the test modem to an 800-volt peak amplitude electrical surge, current-limited to 100 amps, over a period of time consisting of 10µs (microseconds) risetime and 560µs decay time to half-voltage peak.

The Zoom V.34X "continued to go on-hook and off-hook and send data after the electrical surges of FCC Part 68 were applied," according to CCL. In contrast, the Courier V.Everything, USR's flagship faxmodem, "failed to go into an off-hook mode after the FCC Part 68 metallic surges (at both 800 volts and 600 volts) were applied." The CCL noted that, "Units in the actual field that experience lightning surges and remain in a continuous on-hook state create an inconvenience to the user since the unit cannot be used and also requires the time and expense to have the unit repaired."

CCL's John L. Chase states, "A popping sound was heard and an electric flash was seen when the 800-volt metallic surge was performed on the unit." The CCL repeated the surge test at 600 volts peak amplitude with a new USR V.Everything modem. Again the USR modem failed.

"These test results demonstrate the high reliability and robust performance of Zoom modems," said Zoom President and CEO Frank Manning. "ZoomGuard™ technology raises the cost of goods of Zoom's modems, but drastically reduces the probability of field failure from lightning compared to U.S. Robotics and others. ZoomGuard is one of a number of reasons that Zoom modems have unusually few field problems."

"Our ZoomGuard lightning and surge protection program has dramatically reduced returns due to modem failure," said Manning. All current V.34 Zoom modems and ISDN products are protected by ZoomGuard.

Copies of Communication Certification Laboratory's test report and letter summarizing the test report are available from Zoom Telephonics at no charge on request.

Lightning is the most common cause of modem failure. Direct hits to overhead lines occur, but far more common is the induced surge on a buried cable. According to Roy Carpenter, Chairman of Lightning Eliminators and Consultants, "Lightning presents one of the greatest threats to military information systems; probably the most significant, next to military action by an enemy."

In the United States, the high point of thunderstorm activity is in western Florida, with a ripple effect out from this focus of lightning activity. The high lightning level of the southeast extends all the way west into eastern Texas. In addition, the United States has intense thunderstorm activity in areas of Colorado, New Mexico and Arizona. Even in the relatively low lightning activity area of the central United States, "there are about 20 strikes per square mile to farmland per year," according to Carpenter. April is the beginning of lightning's primary season that extends over six months, ending in early October.

CCL is a full service, independent, electronic testing and certification laboratory, located in Salt Lake City, Utah. CCL also provides EMI and safety testing services. CCL has no affiliation with any manufacturer and their client base is not concentrated with any particular manufacturer.

CCL has been an active member in the telecommunication and testing industries since 1971. Its telecom testing services include FCC Part 68, IC CS-03, EIA RS470, JATE, and AUSTEL. CCL was one of the first laboratories to offer testing to FCC Part 68 and was instrumental in the development of the rules. CCL takes an active part on Telecommunication Industry Association's (TIA) Committee TR41.9, which prepared the test procedures for Part 68 and continually works on current Part 68 issues.

CCL has demonstrated its competence to perform testing to FCC Part 68 and Part 15 by being accredited by the U.S. Department of Commerce, National Voluntary Laboratory Accreditation Program (NVLAP). CCL is also accredited by AUSTEL and OSHA and are members of TIA, ACIL, ANSI, IAEI, IEEE, CCT, and TAPAC.

Zoom Telephonics designs, produces, and markets products that link people and their personal computers through the world's largest network, the international telephone network, and connected networks including the Internet and corporate local area networks. Zoom Telephonics is publicly traded on NASDAQ (NASDAQ: ZOOM). Zoom products are distributed worldwide. The Zoom Web Site is www.zoomtel.com.