A two-year-old agreement between National Semiconductor Corp and SGS Thomson Micro-electronics on chips for Integrated Services Digital Networking systems yesterday bore fruit with the announcement of two ISDN chip sets. The companies say that the programmable combo and digital interface device are their first ISDN chip products to conform to CCITT standards. But despite speculation that the partnership would have news on its recent efforts to secure alliances with software houses no details were available. The TP3076/ST5075/6 Programmable Combo for digital terminals is derived from second generation pulse code modulation coder-decoder and filter devices for use on ISDN and digital telephone applications. The second jointly-developed ISDN device is an S interface, which comprises a 192Kbps bus structure carrying two 64Kbps B channels alongside a 16Kbps D channel. Called the TP3420/ST542OA S, the device delivers ISDN applications to the customer. The transceiver supports transmission over one mile in point-to-point configurations and 200 yards in point-to-multipoint according to the CCITT 1.430 recommendation. Implementation of features for terminal equipment, terminal adaptor, network terminations and PABX line applications is also included. In addition National Semiconductor announced a digital adaptor and a communications controller for ISDN applications that will be second sourced by SGS Thomson. Dr Theodore Irmer, director of the CCITT stated that ISDN is now becoming a reality and that most of the regulatory and standards issues have been resolved. NatSemi and the Franco-Italian chip company claimed that significant research and development, manufacturing and marketing resources have been committed into global connectivity applications which they view as a joint activity. At present, the partnership is jointly developing further ISDN chips including a 2BIQ U Interface Transceiver and a set of products for terminal applications based on the GCI interface. National Semiconductor first joined forces with Thomson SA in 1979 to develop the Combo coder-decoder/filter products in conjunction with the French Telecommunications Research Laboratory CNET.
