PDM-30A Primary PCM Multiplexer provides flexible modular VLSI based solutions which provide voice & data applications by TDM on 2,048 MB/s E1 stream. The equipment is fully solid state, field proven and adopts state of the art technology conforming to ITU-T standards. PDM-30A has been designed to connect 30 subscribers to an Analog or Digital exchange. It multiplexes 30 voice or data channels of 64 Kb/s or combination into a stream of 2 Mb/s tributary. Clock distributor interface required for leased data circuits in an integral part of PDM-30A. PDM-30A, a rugged design equipped with twenty slots for various units. Four of them are the common units and the remaining sixteen slots are for channel & signalling units, which provides a variety of user services. All the channel units are HOT SWAPPABLE and different types of channel units can be placed in PDM-30A simultaneously with arbitrary combination.