Patent GB-855975-A (GB)
Title: Improvements in or relating to pulse distributing arrangements
Inventor: GALVIN JOHN LESLIE
IPC: H04M15/10
Filed: 1958-06-10
Abstract: 855,975. Automatic exchange equipment. AUTOMATIC TELEPHONE & ELECTRIC CO. Ltd. May 4, 1959 [June 10, 1958], No. 18463/58. Class 40 (4). In an arrangement for producing pulses (such as metering pulses) on different leads, pulses on different leads occurring at different intervals, a counting chain is used to provide pulses on one lead at a basic rate, and pulses on other leads occurring at intervals which are multiples of the basic interval are obtained over the banks of a uniselector stepped once per cycle of the counting chain. Pulse - distributing arrangements.-Assuming change-over switch CO is in the position shown and switch BTS in equipment PDB is in position 1, operation of the start relay ST of equipment PDA which connects the pulsing relay TA of the first equipment to a source of clock pulses CP of frequency one/sec. Relay ST also closes a self-drive circuit for switch TS, which is opened by relay K when the switch reaches a position identical to that of switch BTS of the second equipment, i.e. position 1 in this case. Relay K brings up KR which connects the pulsing lead POL to the equipment PDA. Pulses from contact tal step a counting chain containing five pairs of relays PA, ZA ... PE, ZE either directly in the case of the last three or indirectly as described below in the case of the first two. Thus PA operates on the beginning of the first pulse and locks up in series with ZA, which also operates, at the end of the pulse and so on. When all pairs are operated successive succeeding pulses release PA, PB ... by differential action, which results in the consequent release of ZA, ZB ... However, some of leads ZAL ... ZEL may be connected together, e.g. ZCL, ZDL and ZEL so that when PC is released by differential action so also are the succeeding relays PD, PE. The basic period (at the end of which TS is stepped) is determined by the number of pulses required to complete a cycle starting and finishing with all relays of the chain released, and the duration of the cycle can thus be determined by the interconnection of appropriate ones of these leads. The output side of equipment is provided with terminals 1M, 2M, 3M, 6M, 12M and 24M which are to be pulsed at intervals of 1, 2 ... 24 times the basic period. Each terminal such as 1M is connected to a distribution relay PO, which operates when 1M is pulsed to provide a meter ing pulse on a corresponding lead MRD, and a check pulse which is applied to a corresponding point 1C. On the first pulse of a cycle, the pulse from ta1 feeds terminal 1M directly and the check pulse reverted over terminal 1C steps the chain. If switch TS is at an odd position, lead 2M is pulsed over TS2 at the second clock pulse and the check pulse is reverted over TS3 to step the chain. If TS is at an even position however the clock pulse is directly applied to the chain via banks of TS2, TS3 and no metering pulse is emitted. At the end of a basic period the tal pulse is applied to wiper TS4. If the latter is on any of the 1st, 4th, 7th ... steps, terminal 3M is pulsed and the check pulse on terminal 3C operates relay K over TS5 to step the switch. If the switch is on any of its 2nd, 8th ... steps the 6M terminal is pulsed and the check pulse on 6C steps the switch. Terminals 12M, 24M are similarly provided. If at the end of any basic period no metering pulse is required, stepping of the switch is provided for by direct interconnection of the appropriate bank contacts of TS4, TS5. Faulty operation and change-over to standby equipment.-An S-pulse is applied periodically to lead SP to energize S which locks up over its middle winding. Release of this relay is effected by the energizing of its opposing upper winding. With TS in an odd position this occurs provided a check pulse is received on terminal 1C and provided the counting chain responds thereto to apply a pulse to the wiper TS2. This pulse also operates CK which locks. During the next cycle release of S is effected over an even contact of TS3 (and CK is released by differential action) so that if TS has failed to step S remains up. If S fails to release then 30 seconds later relay Z operates to a Z-pulse on lead ZP. Relay Z releases AL to disconnect TA from the clock pulse source CP. Relay X then operates to change over the switch CO which operates the start relay BST in the alternative equipment and releases ST. Relay CO also changes over the meter distribution leads to the alternative equipment and brings up Y. Switch of the alternative equipment is now driven under control of relay BK to a position corresponding to that at which TS is stopped. Switch CO also operates BAL which connects up the clock pulse source CP to the alternative equipment. Relay Y brings up an alarm over lead DA. When a maintenance man answers the alarm by throwing key KRA, relay SA operates, releasing X. If the second distributor now fails an " immediate alarm " is brought on over lead IA. The start relay ST can be manually operated by the throwing key KA. The switch TS then runs to the terminal marked at that time by BTS and thereafter steps under the observation of the maintenance man. Automatic change-over can be prevented from occurring by throwing key KC which then also causes the immediate alarm to come up on a fault occurring. Reduced rates.-For night working at halfrate lead NR is energized to bring up relay MRC. This switches in a frequency division circuit MA, XA which only transmits every other pulse from ta1 to the counting chain.