Patent GB-410191-A (GB)
Title: Improvements in automatic telephone systems
IPC: H04Q3/42
Filed: 1932-11-14
Abstract: 410,191. Automatic exchange systems. CORLETT, W. D., 82, Marathon Street, Kensington, Johannesburg, South Africa. Nov. 14, 1932, No. 32202. [Class 40 (iv).] Impulses transmitted from a prepayment substation in accordance with the number or value of coins inserted advance an automatic switch from a position corresponding to the zone of the wanted party to a predetermined position in which the talking circuit is completed. The same switch may measure out a series of time-intervals after each of which a further payment is required and after a predetermined number of such intervals the connection may be definitely broken down. Three applications are described. First system, Fig. 1. The payment-controlling switch FB is associated with a first code selector and, after movement to its second position on the operation of the answering supervisory relay D, either remains in this position or moves to its 3rd or 4th position according to the condition of relays 1FD, 2FD, controlled over a zone-determining vertical wiper VW. In positions 2-4 of FB, the feed relay L is disconnected and is not again connected up until position 5 to which FB should be advanced by coin-controlled impulses transmitted over a simplex circuit to relay FR. If the coins are not deposited within a given time, relays X, Y operate successively over leads S, Z and release the connection. If the coins are correctly deposited, switch FB is advanced by timed-impulses from lead 6 to position 11 in which relays AA, BB, operate and a warning tone from lead 4 is connected to the b-wire. A second warning signal is applied in position 13 and the switch then moves to position 14 to which the connections are the same as for position 2 so that a further test for deposited coins occurs as before. At the end of the second conversation period the connection is definitely broken down owing to wipers fb1, fb2 moving off their multipled terminals. In place of the vertical wiper VW, zone-determining signals might be sent back from the registercontroller. Second system, Fig. 2. In a direct-impulsing system, a zone-determining switch FD and the payment-controlling switch FC are associated with a relay group leading to the first selector. When seized, relays A, H, operate, and the first one or two digits are repeated to magnet FDDM to operate one or both of the relays DF, SF, switch FD then being restored to normal. When relay D operates it disconnects the feed and energizes relay MD which advances switch FC to position 2, 3, or 4, dependent upon relays DF, SF, as in Fig. 1. Coin-controlled impulses operate differential relay FR to advance FC to position 5 in which relays PM, IP, operate and restore the feed. If the coins are not deposited within a given time, switch FD is stepped by impulses over lead 14 and wiper fc2 to position 4 in which a local holding circuit for relay A is opened and the connection is released. If the coins are properly deposited, switch FC is stepped over lead 14 and wiper fc5 to measure out a conversation interval. In position 25 a warning tone is supplied over lead 13 and the switchthen moves through position 1 to position 2, 3, or 4, in which the previous test for inserted coins is made. At this time the feed circuit is maintained over d1, ip2,fd2 and the connection will be broken down, if no further coins are deposited, by the movement of switch FD. If digit 0 is dialled to call a toll operator, relay TR energizes to cut out the coin-testing apparatus and complete a direct metallic circuit to the first selector. Third system, Fig. 3. The apparatus shown is associated with a satellite discriminator, which sends back impulses over lead 27 according to its setting to set a relay group TF, SF, DF, under the control of which switch FC moves to position 2, 3, or 4. Relay S operates to disconnect the calling party's feed which was previously supplied from the discriminator. When the called party replies, relay D operates and coin-controlled impulses are repeated by relay FR to advance FC to position 5 in which S is released. If the required coins are not deposited, relays FP, SP, TP, operate in succession and release the connection. If the coins are correctly deposited switch FC is advanced by impulses from lead 29 until the beginning of its bank is again reached when the deposit of further coins is tested, but with the feed retained owing to the operation of relay IP. Specification 358,983 is referred to.