Patent GB-270026-A (GB)
Title: Improvements relating to telephone systems
IPC: H04Q3/42
Filed: 1926-02-16
Abstract: 270,026. Siemens Bros. & Co., Ltd., and Grinsted, W. H. Feb. 16, 1926. Automatic exchange systems.-In order to provide the usual intertrain pause when sending impulses from a register controller set, the counter switch comprises a normal contact, digitworking contacts, and further contacts which provide the fixed pause, a 25-point switch being preferably used. The switch hunts for the marked contact, at the same time sending cut impulses, is then self-stepped over the remaining marking contacts, and is then stepped alternately by self interruption and an interrupter. Where for instance double selection occurs, an abnormal pause may be required, and this is obtained by operating a polarized relay, which acts to open the switch circuit and to keep the impulsing circuit closed. Arrangements for connecting to an operator by dialling O or three code digits are described, and also means for giving a signal and busying the register controller if the interrupter motor fails. Delay in dialling or dialling a dead code number are also dealt with. Seizure of register-controller. When a call is made, a first code selector at the exchange is seized, and in turn seizes a free ' A ' digit selector. When the first digit is dialled, the ' A ' digit selector seizes a free register-controller over a circuit from earth over wire c, contacts co3, pa3, ra1, ds2, busy key K, polarizing winding 1 of relay D to battery. The ' A ' digit selector switches through, and relay A operates over the wire p from battery at the first code selector. Relay B energizes to earth at busy key K, connects earth to wire c at b2, and to relay D (1) at b9, and energizes relays BX, MS, the latter of which starts the interrupter motor. The continuously-rotating cam earths in turn contacts S, Z, the former of which now energizes relay TP (1) over contacts b4, and relay TP locks up over its winding 2, contacts tp2, w5, c1, key K, contact b1, key K to earth. When the interrupter contacts I<1> are closed, relay LCR energizes over contacts lcb1, lcb2, co1, b1 and when the interrupter contacts open, LCB energizes in series therewith, connecting the interrupter F<1> across the wires a, b, and short-circuiting it at sa1. When the contacts of interrupter I<2> next close, relay CCA operates in a circuit [earth over contact b1, strapped contacts of key K, contacts lcb3, wire 27, wiper SC4, wire 26, contacts sz3, I<2>, ccb2, CCA, battery]. When the interrupter opens, relay CCB (1) energizes in series with CCA, connecting the interrupter I<2> over contacts ccb2, bx1, wire 8, magnet SSM to battery. Earth at contact ccb1 energizes magnet SCM to step the wipers of the out-controller SC to their second contacts, the circuit of relays CCA, CCB being broken. Registering digits. Relay A repeats the second train of code impulses to the vertical magnet VM of the switch BC in a circuit [earth, key K, a1, b3, mba2, relay C, wire 2, wiper DD1. VM, battery]. Relay TP is released at c1, and relay DS is energized over c2, opening at ds3 the circuit of the lamp L, which was closed previously at bx3. At the end of the train relay C releases and the in-controller DD is stepped, a circuit [earth, key K, b1, strapped contacts of key K, c2, ds4, line 1, DDM, battery], being opened when DS releases. The last train of code impulses is repeated over wiper DD1 to magnet RM of the switch BC, after which DD is stepped to its third contacts. The numerical trains of impulses now operate in turn the magnets MM, MH, MT, MU, of the marking switches DM over successive contacts of DD1, which remains on its seventh contacts. Impulsing. When the third code digit has been registered, relays CCA, CCB re-energize over wiper SC4, wiper DD2 to earth, and the counter-switch magnet SSM. is energized over wire 8, interrupter I<2>, sz3, wire 26, wipers SC4, DD2, to earth, and the switch is stepped by the interrupter. On its second contacts, relay SA is energized [wire 14, SS3, wire 17, lcb4, lcb3, key K, b1 to earth]. The counter-switch continues stepping, impulses being now sent over the wires a, b by the interrupter I<1>, the short-circuit of which has been removed at sa1. When the contact marked in the bank of wiper SS1 by the terminal W connected to selected contact of wiper BC (1) is reached, relay SZ energizes [wire 10, wiper SS1, W, X, BC1, SC2, DD2, earth], shortcircuiting P at sz1 to stop impulsing, and closing a self-stepping circuit for the counting switch [SSM, ssm, wire 7, sz2, wire 16, SS5, wire 17, earth]. Relay SZ locks up over sa3, sz4, and release relays CCA, CCB. When the switch leaves the 13 contacts, relays SA, SZ de-energize, and break the self-stepping circuit, but the switch self-steps to the 15th contact over wiper SS4. The magnet SCM, energized over contacts sz5, ba2, is now de-energized and the switch SC steps to its third contacts. Relay CCB energizes [CCB(2), wire 9, SS4, wire 15 to earth] and locks up over its winding 1, SC4, DD2 to earth, and the interrupter I<2> steps the switch SS to its 16th contact, and the switch is then alternately self- and interrupter-stepped to normal. Five more translated digits are similarly sent, and the interrupter circuit for magnet SSM now passes over the 8th contact of wiper SC4 and the off-normal sector of wiper H3 of switch DM so that the thousands digit cannot be sent till the hundreds digit is registered; similarly the sectors for the wipers T3, U3 are connected to the 9th and the 10th - - 12th contacts of wiper SC4. When all the digits have been sent, in accordance with the marked contacts of wipers M1, HI, T1. V1, the out-controller SC is on its 12th contacts. Release of register controller. When the counter switch SS reaches its 19th contacts, relay CO energizes over wipers SS2, SC2, DD2, locks itself, de-energizes relays LCA, LCB, TP, releases the ' A ' digit selector at co3, operates the meter Q over key T, co4, and key K, and closes a selfstepping circuit for magnet DDM over relay RA. When the in-controller reaches its next normal position, it closes a circuit for the magnet MM [relay RA, co6, wire 4, DD3, M2, off-normal sector, mm, MM]. The switch M, and in turn the switches H, T, U, self-step to normal, when the release magnet ZM is energized over its off-normal contacts u, and the switch BC returns to normal. Relay RA operates an alarm to give warning of delayed release, and flashes the lamp L through the interrupter I3. Relay CCB deenergizes, the switch SS returns to normal [SSM, ssm, wire 7, lcb6, SS5, wire 18, lcb7, co6, RA] and the switch SC steps to its second normal position (SCM, scm, SC1, wire 22, lcb5, co6, RA]. When the A ' digit selector was released, relays A, B, CO, BX, D (1) were released, but the self-stepping circuits of the switches were held from relay RA over contacts b7 instead of co6, relay RA releasing when all the switches are again normal. Delayed or dead code number dialling. All spare exchange-code contacts X are commoned to a contact sc and since the letters corresponding to the numeral 1 are, in the area under consideration, not required, the contacts in the first level and the first contacts in remaining levels of the wiper BC (1) are commoned direct to contact sc and to wire 20, so that if a dead code number is dialled, relay M energizes over wipers BC (1), SC2 (contact 2), DD3 (contact 3) to earth. Contact m1 opens the input impulse wire p and connects relay A to battery over a resistance, and m2 opens wire b. The counter switch operates as usual, but when it reaches its 12th contact, relay SZ energizes [SZ, wire 10, SS1, wire 12, m3]. On reaching the 14th contacts, relay SA releases and switch SC steps to its 3rd contacts, so that relay M releases, de-energizing relays A, B, LCA, LCB. The homing circuits of the switches are closed as before, contacts b7 being closed. If dialling is delayed, relay TP remains energized when the contact Z is earthed by the rotating cam, and relay M (1) is then energized, initiating release as above. Operation on failure of interrupter motor. When the second code digit is recorded, relay PA operates [battery, PA, wire 24, first bank contact and SC3, wire 25, ds1, wire 6, DD2, wire 3, key K, contacts b1, key K to earth], and locks up to key K. An alarm relay AP is energized, and the lamp L and relay M (1) are intermittently operated. Wire p is opened and a distinctive tone sent to the caller from the first code selector. Relays A, B release in turn and the controller returns to normal. Relay PA remains locked until key K is pressed, so that contact pa3 remains open to prevent seizure of the controller. Connection to operator. (a) By dialling digit O. Wires outgoing from the 10th level of the ' A ' digit selector have their a and b wires crossed, so that when relay LCB operates and erergizes winding D (2) over the a and b wires, relay D operates. Relays A and B operate as before. Relays MBB. MBA energize over contact d<1> and wiper DD2, and lock up over contact mba3, winding D (2) is short-circuited, and the circuits of the recording switches are opened at mba2. The counter magnet energizes from wiper SCO over contacts mba4, lcb3 to earth instead of over wiper DD2. Relay MBB connects the wiper of switch BC to certain contacts X, and five trains of code impulses are sent out. The wiper mbb6 is cross-connected to contact co, so that when the out-controller is on its 7th contacts, relay CO energizes [CO, wire 13, wiper SS2 and its 19th contact, co, mbb6 SC2, wire 28 to earth to initiate release. For a lesser number of impulse trains, the corresponding wiper mbb would be similarly cross-connected. (b) By three code digits only. The corresponding contact X connected in the bank of wiper 6 is cross-connected to contact co and the impulsing circuits are normal. Suppressing one or more translated digits. The necessary contacts X are cross-connected to the contact deo so that the switch SC is self-stepped on while the swit