AT&T Microelectronics wants to help OEMs get ISDN-ready

BERKELEY HEIGHTS, N.J. -- In light of the explosive growth in online services and telecommuting, AT&T Microelectronics is now enabling premises equipment makers to market products with built-in access to the "Information Superhighway."

Thanks to AT&T, original equipment manufacturers can differentiate their products so they take advantage of new high speed Integrated Services Digital Network (ISDN) lines that are available from most telecommunications service providers.

AT&T components for "ISDN-ready" equipment include the T7256, the first and only single-chip integrated circuit to implement the entire NT-1 interface between ISDN lines and premises equipment. Also offered is the T7250C Enhanced User-Network Interface for Terminal Endpoints (UNITE), a complete solution enabling OEM's to cost-effectively add ISDN capability to communications and computing equipment.

"Customers are finally ready to embrace ISDN services because they perceive direct benefits with higher data throughput," said Kelly Mennell, ISDN product marketing manager, AT&T Microelectronics. "With these new components, we're helping both equipment makers and service providers break the price point barrier that has kept customers from buying ISDN-equipped products."

The T7256 single-chip NT-1 (SCNT1) complies with all of the ETSI and ANSI requirements defining this standard ISDN network termination. Its four major on-chip interfaces consist of the standard 2-wire U-interface (2B1Q); the 4-wire S/T interface; a serial microprocessor interface; and a TDM (time division multiplexed) interface allowing access to 2B+D data.

The device's flexibility and full feature set allow manufacturers to enter the market rapidly and still meet the most stringent telephone company or PTT requirements. In addition to NT-1 applications, the T7256 can be used in terminal adapter equipment, interfacing the two-wire digital network with voice and/or data ports, and providing local switching of terminal voice/data.

The device operates in standalone mode to provide activation, control and maintenance functions, but also includes a serial microprocessor interface, and supports direct codec connection. This allows designers to inexpensively add extra maintenance and control functions, via an external microcontroller.

Low-power operation--the device consumes just 270mW when active--and an idle mode which consumes 35mW, allow the device to support line-powered applications.

The T7250C UNITE Chip is an enhanced version of a field-proven Basic Rate line transceiver for 4-wire S/T interface to terminal endpoints. It is offered bundled with Layer 2 and 3 ISDN terminal protocol software from vendors such as Link Technology so that manufacturers can significantly reduce time to market.

With Link Technology's technical support for system implementation, manufacturers now have a ready-made solution to add an Information Superhighway "on ramp" to such products as ISDN telephones, video phones, ISDN terminal adapters, PC and workstation motherboards and ISDN plug-in cards.

The T7250C UNITE is an updated version of a field-proven device that has been enhanced to meet U.S. and European conformance testing, and fully complies with ITU and ANSI specifications at the S/T reference point. Additionally, it features analog interfaces to low-capacitance transformers which provide an increased margin to CCITT 1.430 impedance templates or to reinforce isolation in certain applications.

Both the T7256 SCNT1 and the T7250C UNITE chips are packaged in 44-pin PLCC packages. Production quantities are available now, with the T7256 priced at $23.90 each and the T7250C at $7.87 each in 10K orders.

For additional information, customers should call the AT&T Microelectronics Customer Response Center, 1-800-372-2447, Dept. P46; (in Canada, 1-800-553-2448, Dept. P46;) for customers outside of North America, fax: +1-610-712-4106. Information may also be obtained by writing to AT&T Microelectronics, Room 21Q-133BA, 555 Union Blvd., Allentown, Pa., 18103.

AT&T Microelectronics offers a full line of high performance components and electronic systems to original equipment manufacturers, for applications in network computing, telecommunications, cellular/wireless and video. Included in the product line are CMOS, Bipolar and High Voltage custom and standard products, communications devices, graphics and speech processors, interconnect products, lightwave products, and power supplies.

KEYWORDS: isdn, oem, premises_equipment, t7256, nt-1, t7250c, unite