The Multiple Rate Digital Switch (MRDX) is an upgraded version of Zarlink's MT8980D Digital Switch (DX). It is pin compatible with the MT8980D and retains all of its functionality. This device is designed to provide simultaneous connections (non-blocking) for up to 256 64 kb/s channels or blocking connections for up to 512 64 kb/s channels. The serial inputs and outputs connected to MT8986 may have 32 to 128 64 kb/s channels per frame with data rates ranging from 2048 up to 8192 kb/s. The MT8986 provides perchannel selection between variable and constant throughput delays allowing voice and grouped data channels to be switched without corrupting the data sequence integrity.