Adaptation-Layer Chips Eliminate External Devices

The highly integrated AAL1 SAR (segmentation and reassembly) ICs contain on-chip phase locked loops (PLLs) and static random access memory (SRAM) to eliminate up to six external devices in TDM-to-ATM (time division multiplex to asynchronous transfer mode) conversion. Two versions, the MT90528 with 28 ports and the MT90520 with 8 ports, are available. Both use per-port PLLs for network synchronization and SRAMs for channel buffering. Low voice processing delay (latency) eliminates the need for voice echo cancellers (VECs). Both devices receive constant-bit-rate (CBR) traffic from TDM ports at 1.544/2.048 Mb/s rates and convert it to 53-byte cells for transport over ATM networks. Prices are $200 for the MT90528 and $88 for the MT 90520 in 1,000 piece quantities. ZARLINK SEMICONDUCTOR INC., Ottawa, Canada. (613) 270-7115.