GB1340569A - Coi-operated telephone systems - Google Patents

Abstract

1340569 Coin box telephones SIEMENS AG 28 April 1971 [6 May 1970] 11785/71 Heading H4K Metering pulses arriving at a prepayment substation are used to generate coin collection pulses - such that over a cyclical period the amount of fee determined by the metering pulses is equal to the amount determined by the coin collection pulses. In the German telephone system described the metered fee is 18 pfennig and the minimum coin prepayment is 10 pfennig so in a single conversion cycle of 5 meter pulses, 9 coin collection pulses must be generated to provide parity. Thus in this system each meter pulse must cause two collection pulses to be generated four times and the fifth meter pulse should only generate a single collection pulse. In the system shown operation of the substation switch hook closes contacts r and h which energizes relay S and when contact 1s closes relay St operates. Contact 1st changes over to drop relay S and the system is operational. Incoming reactor pulses on terminal Z operate relay I which triggers a coin collection pulse which is applied to a coin checking and collection arrangement not shown, and by closing contact 1i allows selector relay WR to drive to the first stage. Simultaneously contact 2i opens to drop relay St after a delay which is less than the duration of the meter pulse. Cessation of the meter pulse causes I to drop and relays S and St operate again with relay S dropping when contact 1st operates. Contacts 2s and 2st are both operated owing to the delayed drop of relay S so that relay I operates again to provide a second coin collection pulse. Selector WR is driven to position 2 where relay coil St2 is energized which prevents further repetition until the next meter pulse arrives. Coil St2 will be energized at the 2, 4, 6, 8 and 9 positions of the selector and the circuit will thus provide the required number of coin collection pulses. Contacts wr and w operated by the selector ensure that if a call is completed during the cycle the selector homes. Different metering fees can be accommodated by changing the output connections of the selector. In a further modification, Fig. 2 (not shown), plug connections are provided to enable the fee rate to be changed and a relay chain is used to generate the coin collection pulses. The coin checking and collection circuit is also shown.