Patent GB-824352-A (GB)
Title: Improvements in or relating to electrical signal generators
IPC: H04M15/10
Filed: 1956-12-07
Abstract: 824,352. Automatic exchange systems. GENERAL ELECTRIC CO. Ltd., and SPEED, R. F. B. Dec. 9, 1957 [Dec. 7, 1956], No. 37524/56. Class 40 (4). In a circuit for producing meter impulses and designed to deal with calls on a multiplex basis, a counting circuit receives pulses in the time position of the call in question and a correspondingly timed pulse is also inserted in one of a plurality of stores indicative of the rate of charge. Each store feeds a gate opened when the counter reaches a certain count for a given pulse position, so that a metering pulse is emitted. This pulse also zeroizes the counter in respect of that particular pulse position. As shown, Fig. 1, each store 25... 29 is associated with a different metering rate and can store 100 time-spaced pulses each indicative of a call. When a call is set up, the appropriate pulse is applied to lead 33 and one of leads 40 ... 44 is energized by the translator in accordance with the metering rate appropriate to the call, so that the pulse is inserted into the appropriate store, e.g. 28. The counter 11 consists of stores 1 ... 10 arranged to store pulses received over lead 13 at a rate of one per half-second for every one of the 100 pulse positions. These pulses appear only for the duration of a call on that particular channel. The stores 1 ... 10 store the count in binary form. When the called subscriber answers a pulse in the appropriate time position is applied to lead 24. This pulse zeroizes the counter in respect of this time position and is also emitted on lead 32 as the first metering pulse. When the count reaches a value represented by storage of the pulse in stages 6, 7, 8, 9 a pulse from these stages is applied to gate 46 in coincidence with a pulse received from store 28. This gate thus emits a metering pulse over lead 32 and at the same time zeroizes the counter which thereupon proceeds to count out the next interval and so on. To terminate the supply of metering pulses the lead 37 is pulsed at the appropriate time position to delete the pulse from the store 28. In the counting chain, Fig. 3, the first pulse on lead 13 is inserted in the 100Ás delay line 50 and the second pulse in this time position half a second later coincides with the delay line output to open gate 52, the resulting impulse deleting the pulse from store 50 and being passed to be stored in the second stage store 51. The next pulse is stored in delay line 50 so that the next pulse can pass both gates 52 and 53 to the third stage of the counter and can delete the pulse in stores 50, 51. Operation in this manner causes the count to be registered in binary form. A device 48, Fig. 2, may be inserted in the lead 32 to give a longer metering signal consisting of a plurality of pulses in the required time position, by delaying the zeroizing of the counter for 100ms. 100Ás pulses are applied to lead 67 so that during this period pulses on lead 32 can be inserted in store 62. 100ms later a 100Ás pulse on lead 68 causes gate 66 to emit, over lead 24, the stored pulses which zeroize the counter, and also delete the pulses from store 62. During this 100ms period the stored pulses are emitted over lead 32. Variable rate metering for different times of day. Two separate gates may be inserted between each of stores 25 ... 29 and lead 32 each of the pair of gates being responsive to different combinations of outputs from the counter, means being provided to enable one or other of the pair of gates at different times of the day. Detailed circuits of the delay line are given.