Artificial traffic machine for automatic telephone studies

This machine is designed for the production, distribution and analysis of artificial traffic in experiments on switching arrangements. That described is limited to the study of a two-group grading, but the principle admits of extension. A stream of steel balls is directed on to a fixed large steel ball, and are so scattered in a random manner over a number of irregularly placed channels. Those which enter represent originated calls; the remainder are returned to the main supply. The balls representing calls pass to an aluminium runway with holes representing outlets, each being provided with a busying device which closes it for a certain period after a ball has entered. A ball, finding all the outlets closed, passes to an overflow bin and represents a case of congestion. The balls entering outlets may be passed to a further runway representing a further switching stage. Means for imitating a two-group grading are described. The method of making the tests and some typical results in cases capable of being treated mathematically are given. An improved machine, in which the switching arrangements are represented by groups of relays and message registers, is proposed.