PCM and TDM operation

Time division multiplexer is a digital processes that can be applied when the data rate capacity of the transmission medium is greater than the data rate required by the sending and receiving device.

·        After the Encoding each byte comes to the multiplexer, then multiplexer gather 30 bytes together (in every125 µs).

·        Then these 30 bytes (channels) are gathered as Frames. It is called E1 carrier.

·        Before multiplexing synchronizing bit and signaling bit is added to the frame.  Synchronizing bit is in the 1^st time slot and signaling bit is in the 16^th time slot.

·        Now this frame has 32 bytes and one by one goes to the destination end time division de-multiplexer.

·         De-multiplexer decomposes each frame by discarding the framing bits and extracting each character in turn.