MT90502

The MT90502 Multi-Channel AAL2 SAR bridges a standard TDM (Time Division Multiplexed) backplane to a standard ATM (Asynchronous Transfer Mode) bus. The device provides the CPS (Common Part Sublayer) and SAR (Segmentation and Reassembly) engines. The MT90502 has the capability of simultaneously processing 1023 bi-directional CIDs (AAL2 Channel Identifiers) and 1023 bi-directional VCs (Virtual Circuits). The device can be connected directly to an H.110 compatible bus. The TDM bus consists of 32 bi-directional serial data streams operating at 2.048, 4.096, or 8.192 Mbits/s.

The MT90502 directly accepts G.711 PCM (Pulse Code Modulation) and G.726 ADPCM (Adaptive Differential Pulse Code Modulation) traffic for packetisation. For these two data formats, the device also implements silence suppression and comfort noise generation. To support other voice compression algorithms, the MT90502 connects directly to commercially available DSPs through synchronous serial data streams. The Variable Bit Rate (VBR) traffic is HDLC encapsulated and carried over the serial data streams.

The interface to the ATM domain is provided by three UTOPIA Level 1 ports (Ports A, B, and C). All three of the UTOPIA ports can operate in ATM (master) or PHY (slave) mode. Ports A and B combined, architects a compliant UTOPIA Level 2 Multi-PHY port. The MT90502 provides the capability of routing ATM cells to different UTOPIA interfaces, SAR engine or CPU. This feature can be used to connect another MT90502 (to support up to 2046 CID channels or 2046 phone calls) and/or to connect an external AAL1 and/or AAL5 SAR.