Coherent Solves PTT Telecom Netherlands' Combined Echoes.

LEESBURG, Va.--(BUSINESS WIRE)--Dec. 9, 1997--Coherent Communications Systems, the leading echo cancellation and voice enhancement specialist, has supplied further consignments of its EC-6000 and EC-7000 Series 2 Echo Cancelers to PTT Telecom Netherlands, with the total contract valued at just under $1 million. The Coherent echo cancelers are used in PTT Telecom's international switching and GSM operations, highlighting the ability of Coherent's echo canceler to provide exceptional performance for both wireline and wireless applications.

PTT Telecom originally installed Coherent's EC-7000 Series 2 digital echo cancelers, together with all ancillary cabling and equipment. Coherent provided a full turnkey installation, with the system going live in 1996. The latest complement of EC-7000 units is part of PTT Telecom's ongoing expansion program, which includes the provision of international telecoms services under Unisource Voice Service (UVS - a consortium of PTT Telecom, Telia AB, Swiss Telecom and Telefonica) and deployment across PTT Telecom's international network.

Coherent has also supplied its leading edge EC-6000 units to the Mobile Division of PTT Telecom, in order to handle hybrid echo on its GSM network. The cancelers are deployed at the PSTN interface, operating in conjunction with PTT Telecom's Ericsson AXE 10 switches. Commenting on the implementation, a representative of PTT Telecom Netherlands said: "Quality is a major issue for us and we were looking for a good, stable echo cancellation solution which would provide us with the right combination of performance and cost-effective implementation. Our subscriber base is expanding steadily, with over one million subscribers already on the network and plans to hit a target of 2.5 million by the year 2000."

Coherent's focus is to provide telcos, PTTs and network operators with the tools to maximize network performance and voice quality on wireline and wireless networks, across the full range of applications. The Company specializes in providing a complete turnkey service, encompassing all aspects of design, supply, installation and maintenance of the cancelers and associated network equipment. Chris Royden, Managing Director of Coherent's European operation commented on the PTT Telecom Netherlands' contract: "The PTT Telecom relationship typifies Coherent's current market positioning - we have the technology and the technical expertise to solve echo and associated voice quality issues on modern networks, and provide our customers with fast, effective systems implementation. We have a unique ability to provide complete wireless and wireline echo control solutions to operations such as PTT Telecom, enabling them to maintain competitive advantage through improved voice quality performance and complete echo cancellation. It is gratifying to work with them at this important stage of their development, and to see our relationship grow in such a positive manner."

Designed to exceed current ITU-T standards (G.168 Recommendation), Coherent's products provide a flexible operating platform which can be tailored for a range of applications and network environments. At their core is a combination of Coherent's state of the art ASIC devices, patented Non-Linear Processor (NLP) techniques, as well as fast and stable convergence (50mS for combined ERL and ERLE of 35dB) - prerequisites for modern network applications.

The EC-6000 and EC-7000 Series 2 Digital Echo Cancelers support Coherent's range of application-specific software, enhancing the units' adaptability for a wide range of problem-solving in different network situations. Software can be remotely downloaded and upgraded, providing a versatile and cost-effective means of maintaining maximum operational flexibility. In addition, the units feature local loopback facilities, extensive alarm reporting and self-test diagnostics, as well as significantly reduced power consumption for improved performance and reduced heat generation.

Coherent Communications Systems Corporation is a worldwide leader in state of the art voice enhancement technology, spanning echo cancellation platforms and associated network software. The Company's products are used globally by major wireless and wireline telecommunications companies and network operators, including AT&T Wireless, BT, Cellular One, Cisco Systems, Deutsche Telekom, France Telecom, KDD, Mercury, Nokia, NORTEL, Telia, and Telmex, among the extensive list. Coherent is a fully accredited ISO 9001 company, dedicated to maintaining the highest quality standards at every level. The company's US headquarters is located in Ashburn, Virginia, with European activity conducted by Coherent Communications Systems Ltd, based in Abingdon, Oxfordshire, UK. -0-

Also available via, http://www.coherent.com

CONTACT: Coherent

Michele Probst, 703/724-7352

or

Garrett Axford

Georgina Garrett, [phone]

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