Design and Implementation of a Signaling Handling Unit for Electronic Exchanges

Design of a unit which handles functions of line scanning, digit forming, and digit pulsing fully independent of the main processor has been presented. These functions as implemented in conventional systems form a major portion of the real time load on the processor. The hardware unit described in this paper takes care of all these functions with only nominal interaction with the processsor, thereby reducing considerably the real time load. In this unit one very high speed logic assembly is shared by a large number of lines with the help of memory and timing circuits. The same hardware with only minor modifications can be used for telex application also. A typical unit for 1000 lines requires about 300 IC's. This includes the processor interface.