Patent GB-787998-A (GB)
Title: Improvements in or relating to metering equipment for use in telephone systems
Inventor: PEARCE JAMES GORDON
IPC: H04M15/10
Filed: 1954-11-26
Abstract: 787,998. Automatic exchange systems. AUTOMATIC TELEPHONE & ELECTRIC CO.; Ltd. Oct. 17, 1955 [Nov. 26, 1954], No. 34265/54. Class 40 (4). Metering equipment is provided for each outgoing junction at an exchange to supply pulses to a meter according to markings applied to the equipment from an exchange controller. In Fig. 1 a subscriber takes into use a relay set ORS over a line selector and operates a register connector RC to obtain a register REG which stores the exchange and numerical digits of the wanted subscriber. The register takes an exchange controller EXC into use and transfers the digits over an electronic connector EC which may involve a translating function. The exchange controller determines the rate of charge for the connection and transmits the information to all metering equipments MME by markings on a five-lead line 10. When an idle junction is selected by the exchange controller the rate of charge is registered in the metering equipment at that junction and second selectors 1SEL and 2SEL extend the talking path, and leads H and M, to the junction. A lead OP in the relay set ORS is momentarily earthed to lock-up relay MD which energizes relay J. The exchange controller EXC is released while the junction is held by line H earthed in the relay set over a b contact which energize relay H at the junction. When the called subscriber replies, relay D operates to release MD and apply battery to the meter MTR for as long as J holds up. When J falls back the meter is connected. over the M wire to a high-resistance relay MS which locks up in dependence upon relay H. Further metering pulses are applied to the line H by a relay JA and in the first embodiment JA operates to send a single pulse at the end of each time interval determined by a binary counter which counts out the complement to 32 of the digit injected into the counter by the particular combination of markings of the line 10. In the second embodiment a ring counter determines threeminute intervals at the end of each of which 1 to 6 pulses are transmitted by JA depending on which one, or none, of the leads of line 10 is marked. Metering equipment of the first embodiment, Figs. 2 and 3. In setting up a call the exchange controller applies HT to lines HTa, HTb and HTh, and puts a priming potential on tubes LM in all metering equipments to which the relay set ORS has access over the lines LM of the second selector outlets SSO. The exchange controller then applies a signal to lead RM of all metering equipments associated with junction lines of the required route. In every free metering equipment HTb supplies a bias to tube MK and if the equipment satisfies the three conditions of being accessible from ORS, of being associated with a junction of the required route, and is free, tubes LM strike to strike tubes MK and prime tubes SZA, at the same time extending a marking over leads MK(EXC) to the exchange controller. A high speed hunting circuit in the exchange controller responds to the first marked lead MK(EXC) and returns a pulse over the lead SZ(EXC) to fire tube SZA which extends backward marking over the lead SZ and determines the setting of the second selector switches and the response of relays H and MS as already described. In firing tube SZA tube ON is also fired to pull up relay SW, contacts of which disconnect HTb, to immobilize tube MK and consequently mark the equipment busy, and connect HT to remaining tubes. Connection of HT fires tube ST after a delay sufficient for SW contacts to be steady. ST pulses the trigger anodes of tubes MA to ME. It is assumed that leads B, C and E are marked by the exchange controller and ST in consequence strikes MB, MC and ME, which strike permanently primed tubes MBA, MCA, and MEA, injecting a number into the counter by priming tubes CD, ED and JD. Tube D now fires, having a greater delay constant than ST, and pulses tubes AD, CD, ED, GD and JD, of which CD, ED, and JD, are fired. When the marking on lead SZ is found by the second selectors and is extended back to the relay set ORS, ORS releases the exchange controller which ceases to extend markings and removes HTa. In consequence MB, MC, ME, LM, MK and SZA, are extinguished. If, due to a fault, the equipment is not held over the H wire by operating relay H within the time taken to increase the potential on the trigger anode of tube OFF to firing point, from the time contact sw1 pulls back, OFF fires and as its anode load is in common with tube ON, ON is extinguished to release relay SW and return the equipment to the idle condition. With H made, contact h1 disconnects the trigger anode of OFF which cannot then fire. Tube OFF also effects release of the equipment when the subscribers hang up and contact h1 falls back. When relay J falls back after the called subscriber lifts his receiver, relay MS pulls back and connects 180 volt pulses to the anodes of MSA, CP, and PB, at sixsecond intervals. MSA strikes after a delay to cover the closing of contact ms1 and fires tube MSB while priming tube CP in response to the zeroth pulse. Subsequent pulses fire both MSA and CP as MSB conducts permanently. The first subsequent pulse is repeated by CP and applied to AC and PB in the first stage of a fivestage binary counter and fires AC to prime PB. The second pulse repeated by CP to AC and PB therefore causes PB to fire which fires BC. BC is fed from an anode load in common with AC and in consequence when BC fires AC is extinguished. Thus the first stage of the counter is transferred from a left condition with A.C. conducting to.a right condition with BC conducting. When BP fires in response to the second pulse it pulses tube CC in the second stage and as tube CD is conducting, thanks to the markings from the exchange controller, tube PD fires to fire DC and extinguish tube CD, thus transferring the second stage from left to right. Similarly, as tube ED is conducting, when PD fires it fires PF in the third stage which fires FC, and the third stage takes up a right condition. When PF fires tube GC is pulsed and fired, as lead D was unmarked, and the fourth stage takes up a left condition with PK primed. The third pulse sends the first stage from right to left by striking AC. The fourth pulse reverses the first stage from left to right during which PB is struck to fire CC in the second stage which is thereby transferred from right to left. Had all the stages started in the condition of the first stage it would take 32 pulses before the tube KC in the fifth stage would fire. With the tubes CD, ED and JD conducting due to marking, the counter is in a condition corresponding to the twentysecond pulse so that, starting from that condition and operating after the manner described for the next, four pulses, every tenth pulse received fires tube KC and operates relay JA. Contact ja2 diconnects HTd to extinguish tube D and connects HTe to tube LC which fires to extinguish KC which would otherwise hold up JA for a count of 16 pulses. For the time JA holds up, a pulse is applied over ja1 to the meter and when JA falls back HTd is reconnected to fire tube D which pulses the marked stages of the counter to re-register the twenty-second digit. Counting proceeds as before with no alteration in sequence due to the first and fourth stages being conducting in a right condition instead of non-conducting as at the start. The zeroth pulse of the first count is replaced by the tenth pulse of each count preceding subsequent counts, the first count requiring a zeroth pulse due to the fact that the first pulse to the meter comes from the relay set ORS. Metering equipment of the second embodiment, Figs 4, 5, 6 and 7. The manner in which the equipment is selected in relation to its junction line by the exchange controller is the same as in the first embodiment. When relay SW pulls back, HT leads are connected and tube ST fires (Fig. 4) to pulse tubes MAA to MEA. One, or none, of the leads A to E, is given a mark and supposing the maximum charge is being made lead E will have caused ME to strike and prime MEA which fires, when ST strikes, to register the mark after the exchange controller is released. In striking, ST also fires tubes TAA, TEA, and TKA, in a chain of tubes from MS to PTF extending across the top of Figs. 4, 5 and 6, which comprise the binary, ternary and quinary stages of a ring counter which, when pulsed at six-second intervals over contact me2, takes three minutes to complete a counting cycle from the initial condition defined by start tube ST. On the first pulse, and after each additional 30 pulses, tube PTF is fired to cause the operation of relay JA six times to operate the meter over lead M with the exception that the first operation of JA in response to the first pulse does not operate the meter as a contact fp1 is not made. This pulse is absorbed as it is supplied by the relay set ORS as above described. When PTF fires it strikes tubes TL and TNA, pulling back relay JA. PTF also pulses the trigger anodes of tubes BB and BD in a testing chain. If tube MAA were conducting to register an A lead mark, BD would be primed and BB would be backed off. As MAA is not conducting BB strikes and pulses the next stage of the testing chain where CB strikes. CB similarly strikes DB and EB, the latter striking FC as this is primed by MEA conducting. FC primes tube PE in a meter pulse counting chain extending from PE to PTM. Relay JA in operating disconnects HTd, which extinguishes BB to EB in the testing chain, and connects HTe and HTq to fire PT (Fig. 7) and put HT on the meter counting chain respectively. PT pulses tubes PA to PE and PTM in the meter counting chain and strikes PE, as this is primed, which fires EC. As EC and FC have a common anode load FC is extinguished. PT also pulses and fires TO which primes FP and extinguishes TNA to release relay JA which disconnects HTe and HTq to extinguish PT and PE respectively, and connects HTd to fire KO w