ANORDNING FOR INKOPPLING AV EN TREDJE ABONNENT, FORETREDESVIS EN TELEFONIST, TILL EN REDAN UPPKOPPLAD FORBINDELSE MELLAN TVA ABONNENTER

摘要

Electronic time switching telephone system so that the operator can listen in, with the ability to break-in and talk to the correspondents connected to the corresponding exchange, the system comprises an interface modem between the operator's line transformer and the connection network.