STC Plc may be halfway out of the chip manufacturing business, but it is still very much involved in chip design, and has teamed up with VLSI Technology Inc, Santa Clara, California to produce a family of chips for use in Integrated Services Digital Networking, ISDN, products. The first product to use chips developed under the agreement is a new ISDN multiplexer, the IDMX, from STC, and STC says that it cuts the cost of ISDN multiplexing by up to 80%. The new analogue and digital chip sets are used in the multiplexer to implement both the subscriber and the exchange interfaces. It runs at 144Kbps over distances of up to three and a half miles. The chips were developed from the STC spec in five months, using VLSI Technology’s design tools, and are implemented in VLSI’s 2 micron double-level CMOS, integrating up to 80,000 transistors per chip.