ADTRAN introduces Low Voltage HDSL delivery system; units provide safe, effective delivery of HDSL service.

DALLAS--(BUSINESS WIRE)--June 25, 1996--ADTRAN, Inc. (NASDAQ: ADTN) introduced today a new line of HDSL products offering service providers a safe and cost effective means of delivering extended range HDSL service. The announcement was made at the SUPERCOMM trade show in Dallas.

"Traditionally, delivering HDSL to extended distances has called for the addition of local powering for the remote unit or line powering with voltages considered to be unsafe for handling," ADTRAN HDSL Product Manager Keith Atwell said. "ADTRAN's new HDSL system is innovative in that the central office unit provides line power using safe voltages -- without the complication of local powering -- to the range extension unit and the unit located at the customer premises."

HDSL is the repeaterless delivery of T1 service to distances of 12,000 feet. Deploying HDSL to distances of 24,000 feet can be attained by using a range extension device, called the ADTRAN HRE (HDSL Range Extender). Previously, the ADTRAN HDSL system accommodated service providers' needs for low voltage HDSL extension equipment without health hazards or technician training requirements by adding local powering to the unit at the customer premises.

ADTRAN's new Low Voltage HDSL system is the first to provide span powering to the complete extended range HDSL circuit using only negative 130 volts DC. ADTRAN achieved this by developing and engineering state of the art ASICS and powering technology. ADTRAN's new Low Voltage HDSL system includes the HTU-C central office unit, the HTU-R remote unit and the HRE mid-span range extension unit.

"This system offers a safe, cost effective method for extended range HDSL deployment and alleviates the need for local powering," Atwell said.

The ADTRAN Low Voltage 220/E220 HTU-C is the Central Office Transceiver unit which works in conjunction with the HTU-R to establish T1 (1.544 Mbps) data rates over a local loop. The 220/E220 HTU-C plugs directly into a standard 220 Office Repeater Bay (ORB) shelf, or the ADTRAN Enhanced 220 (E220) shelf. When deployed in an E220 shelf, this HTU-C becomes part of a larger HDSL system configuration. Through the backplane of the E220 shelf up to 13 HTU-Cs can communicate with an ADTRAN shelf controller known as the HDSL Fuse/Alarm Control unit, or HFAC. Up to 100 shelf controllers can communicate to a single system controller known as the HDSL Central Office Terminal Controller, or HCOT-CTL. This architecture provides a single point of interface to as many as 1299 HDSL T1 circuits.

ADTRAN was established in 1985 to design, develop and manufacture advanced transmission products for high-speed digital communications. ADTRAN is a primary provider of DDS, ISDN and HDSL digital loop products to Regional Bell Operating Companies and many well known OEMs. The broad selection of customer premises products offered by ADTRAN includes a complete line of DSU/CSUs, a variety of ISDN extension and network terminating products and flexible T1 multiplexers. For more information regarding ADTRAN and its products, call 1-800-326-3700, fax [phone], or E-Mail: [e-mail]. ADTRAN can be found on the Internet at www.adtran.com.

CONTACT: ADTRAN, Inc.

Stacy Thomas, 205/971-8488

[e-mail]

or

Keith Atwell, 205/971-8350

[e-mail]