Patent GB-746131-A (GB)
Title: Pulse counting circuit arrangements
IPC: H04Q3/42
Filed: 1954-03-02
Abstract: 746,131. Automatic exchange systems. WESTERN ELECTRIC CO., Inc. March 2, 1954 [March 16, 1953], No. 6076/54. Class 40 (4). A pulse-counting circuit comprises a pulse divider which controls circuits for operating a series of three relays in all possible combinations, a set of five output conductors connected' to the relays so as to be marked two at a time to indicate any digit, and an additional circuit to mark a single conductor as a trouble indication. When the subscriber at D closes his loop, L and SR operate to return dialling tone. Relay S1 (not shown) also operates to energize ON which operates RA1, while SR energizes secondary offnormal relay ON1. Relay L is of a quick-release type such as is described in Specification 648,656, [Group XXXVII], in which the self - controlled upper winding opposes but does not overcome the lower winding. In response to dialling the first release of L energizes RA to release RA1. Release of L also operates P1 over conductor 105 so that when L re-operates at the end of the impulse P2 operates over conductor 106. The second release of L restores P1 and re-operation of L restores P2. This sequence for pulse dividing relays PI and P2 repeats for subsequent pairs of impulses. During the second impulse while P2 is operated and PI is normal, P3 pulls up to energize P2A, which as explained later prevents the train of impulses affecting the prefix counter 221. At the end of the third impulse with PI, P2 and P3 energized P4 pulls up. P3 falls back at the beginning of the fifth impulse. At the end of the sixth impulse P5 energizes. At the beginning of the eighth impulse when P1 restores P3 re-operates. At the end of the ninth impulse P4 falls back. If due to a fault the impulses continue after a count of ten relays P1 and P2 continue their cycle, P3 releasing at the beginning of the eleventh impulse so that apart from P1 and P2 only P5 is energized and this condition remains with P1 and P2 alternately released and operated until impulsing stops or the register is released. When a digit ends, L holds to release RA slowly and RA1 operates. During the operate time of RA1 the circuit to the right of Fig. 2 functions to mark two of the conductors 210, 211, 212, 214, 217 to operate the digit register 220. If more than ten impulses have been counted wire 210 only is marked and when this registration is transferred to the marker an alarm circuit is energized. The release of RA and operation of RA1 also restores the counting relays. Prefix counter. For certain operator codes the digits 11 are dialled. The first digit energizes P1 and P2 but not P2A. In the interdigital pause ground is applied over conductor 222 to the prefix counter 221 and when the counting.relays are released conductor 223 is grounded to prepare the prefix counter for the second digit. Dialling O. A single digit O is used for calling the operator. Before dialling starts, a relay AS (not shown) energizes. If O is now dialled, P3 and P5 will be operated at the end of the digit so that relay MAN pulls up and locks independently of the registering circuit to break the dial-tone circuit. If some digit other than O is dialled, AS releases to prevent operation of MAN by the dialling of a subsequent O.