GB412177A - Improvements in telephone systems - Google Patents

Abstract

412,177. Automatic exchange systems. WEHREN, E., 11, M³slinweg, Berne, Switzerland. Dec. 16, 1932, Nos. 35728 and 35729. Convention dates, Dec. 18, 1931. [Class 40 (iv).] A coin-freed substation comprises registers set mechanically or electrically in accordance with the first three digits dialled and arranged to give a visible signal of the necessary fee and to co-operate with a device for evaluating the inserted coins so that if the correct fee is inserted the call can proceed, but if not, the connection is broken down when the fourth digit is dialled. The hook switch is slowacting. Mechanical control of registers. The shaft a of the dial, Figs. 2, 3, carries by means of arms e a shaft f on which are mounted hooks g adapted to engage the driving members d of the respective registers Zm<1> .. Zm<3>. The driving members are of different lengths so that when the first digit is dialled only the first register is set and so on. The registers are latched by pawls h. When the fourth digit is dialled a fourth hook engages a fourth member d to operate contact springs. The registers are unlatched by the replacement of the receiver. Electrical control of registers, Fig. 7. Relay JR repeats the digits to back stroke switches ZM<1> .. ZM3. VR<1> is energized throughout the operation and VR<2> during each digit. At the beginning of the first digit JZR <1> is energized and at the end JZR<2> energizes UR<1> which locks, holds ZM<1> and connects up ZM<2>. At the beginning and end respectively of the second digit, JZR<1> and JZR<2> are shunted out and UR<2> holds ZM<2> and connects up ZM<3>. The 3rd digit re-operates JZR<1>, JZR<2> to energize HR which holds ZM<3>. The 4th digit energizes HR<1> which operates contact IV. Indicating fee and controlling breakdown at substation, Fig. 1. The registers select lamp circuits to indicate the fee. The arm Mza is stepped round to a position characteristic of the coins inserted. If the correct fee has been inserted, K is energized and cuts off T which would otherwise be energized over contact IV by the dialling of the fourth digit to break down the connection. Coin collecting and forced release circuits at exchange, Fig. 6. Relay U in the line circuit and C in the test circuit pull up followed by X. In the case of long-distance calls, the reply of the called subscriber initiates the transmission of impulses characteristic of the charge over the wire d to a meter Z<3>. Z' is operated in parallel and energizes Z<2> which locks up. X holds only until the impulses cease and then falls, disconnecting Z<3>. After 3 minutes a further impulse is sent to the d-wire and Z<1>. then energizes K<1> which disconnects the loop from the exchange circuits to release the connection and connects it to a source of A.C. to operate a collecting magnet K<2>. In the case of local network calls, impulses are not sent to the d-wire until the release of the connection and consequent relapse of U. In this case Z<2> operates K<1> immediately to collect the fee.