A Method for Synchronous Data Transmission Between Electronic Data Switching Exchanges

In electronic data switching (EDS) exchanges through connection is performed according to the asychronous time-division multiplex principle. In an input code converter, a polarity reversal on a connected subscriber line or trunk is converted into a line address. With the aid of the central control/storage unit this line address is translated into the address of the serving line; via an output code converter a polarity reversal is effected on the respective line and transmitted to the receiving subscriber. The paper describes how the circuitry in the peripheral equipment of the EDS exchange can be reduced if on the trunks between the EDS exchanges line addresses are transmitted instead of single polarity reversals. To enable a good utilization of the transmission link, the addresses are intermediately stored in a parallel-serial converter and provided with an additional time address in order to recover the original instants at which the polarity reversals have occurred. The principle is illustrated by means of an example, and the possibilities of using PCM channels are outlined.