Studies of telephone traffic with the aid of a machine

It has been found necessary to develop a machine for the study of traffic problems in telephone exchanges. The machine consists essentially of two parts, one to simulate the random occurrence and release of calls, and the other to provide the analogue of the trunking system it is required to examine. A design employing electronic techniques and in which the random feature is obtained from the noise voltages developed by cold-cathode gas-discharge tubes is described. The theory of the machine is discussed and possible future applications of its basic principles are outlined. Some results are given of tests made over the last four years by traffic analyser built in accordance with the principles described. Tests of standard gradings confirm the earlier theoretical work O´Dell.1 The traffic analyser has proved extremely reliable in service.