A 20-line electronic telephone exchange

Many engineers are working on designs for electronic telephone exchanges but at the present time few are in general use. The paper outlines the historical background, the choice of a switching element and the design of a 20-line p.a.x. employing cold-cathode gas-discharge tubes in a space-division switching system. A simplified description of the operation of the exchange is also given. The results of field trials are mentioned and the advantages and disadvantages of the exchange are discussed. An attempt to compare relative cost of electronic and electro-mechanical exchanges has been made and possible future developments are outlined.