Patent GB-464431-A (GB)
Title: Improvements in or relating to automatic or semi-automatic telephone systems
IPC: H04M1/65
Filed: 1935-10-18
Abstract: 464,431. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd. (Hatton, W., and Deakin, G.) Oct. 18, 1935, No. 28835. [Class 40 (iv)] The calling party in a toll call receives an audible or other announcement of the identity of the called party or of the terminating exchange before metering takes place. As described below, the announcing apparatus is associated with the final selector at the terminating exchange, but apparatus for announcing the exchange only may be located at an incoming stage at that exchange or at an outgoing stage at the last tandem exchange. When the apparatus is at the final selector, the announcement is made before ringing occurs, or it may replace the usual ring-back tone. As shown, the announcing apparatus is associated with a common control circuit C serving a group of final selectors FC of the kind described in Specification 331,204, [Class 40 (iv)]. First arrangement, Figs. 1, 2. The selector is set on the wanted line through the agency of tens and units marking switches SMT, SMU, and relays Lt, Ft are connected to test wiper c. If the line is busy, these relays are inoperative, and relay Cc becomes short-circuited over a back contact of Lt, frees the control circuit and sends back busy tone. If the line is idle, relays Lt, Ft energize followed by Ct, and start relay As of the announcing apparatus operates over wire 14. An element FDA generates voice currents representing the exchange name and the digits down to the hundreds of the numbers served by the group of final selectors, and a second element VDA generates voice currents representing the various combinations of tens and units digits. It may be arranged that the element FDA is common to several control circuits. Each announcement is made during the portion T of each revolution of a cam AC, which is started by relay As. Closure of contact 3 connects up relay Sa, which connects the incoming loop over wires 12, 13 and transformer TA to the element FDA. At the next revolution of AC, closure of contact 2 connects up Ua, which transfers the transformer TA to the appropriate wire 6 of the element VDA via wire 10, wiper e of the selector and multiple wire 11. At the next revolution of AC, closure of contact 1 connects up Ra which disconnects Sa and short-circuits Cc over wire 19, so that the control circuit and announcing apparatus are freed and ringing takes place in the usual manner. Second arrangement, Figs. 1, 3. The apparatus A announces over wire E the exchange name and over wires 1-0 the corresponding digits. The cam AC, which is started by relay As, controls contacts which lead to the operation during successive revolutions of relays Sa, Tt, Ta, Ha, Te, Ua, Ra. The incoming loop is thereby connected over wires 12, 13 and transformer TA to the appropriate wires for announcing the exchange name and the thousands and hundreds digits. For the tens and units digits however the circuit includes a wiper of the marker SMT or SMU and multiple wire 16. Relay Ra frees the control circuit and effects ringing as described in the preceding paragraph. Third arrangement. The transformer TA is omitted, and the voice currents are delivered over a two-wire circuit. The selection in the case of the tens and units digits is dependent on a switch which takes up the position occupied by the selector. The sequence of operations take place as in the last arrangement.