The SA8702 (BMTSAC) is a Block Mode Time Slot Allocation Circuit. The device is used to generate 8 consecutive timeslots in one of 4 blocks in a 32 time-slot PCM system. Each timeslot pulse is 8 BLCK cycles long. BCLK is the 2,048 station clock provided by the system. An active MRST will disable all outputs until a valid XSYNC input is recognised. The output TSX is delayed by half a cycle and indicates that one of 8 timeslots is currently active. There are 4 possible modes of operation, selectable by means of the BL0 and BL1 pins (See Table 1).