Innovative developments in dedicated circuits for PABX applications

Describes a solid-state subscriber line interface circuit (SLIC) designed by SGS-Thompson Microelectronics to eliminate the high amplitude transients caused by relay contact bounce. This SLIC developed for analogue cards consists of two devices: the L3000, realised in HV technology that interfaces directly to the line; and the L3090, which integrates all of the control and system interface functions. In the PABX sector, a frequently requested function is the conference call. This function is possible with a single chip due to VLSI technology. The integrated digital PCM processor developed by SGS-Thompson can receive up to 32 channels from the TDM input highway and accepts all the basic rates: 1536, 1544, and 2048 kbit/s