Patent GB-1167177-A (GB)
Title: Automatic Telephone Exchanges.
IPC: H04Q3/62
Filed: 1966-11-09
Abstract: 1,167,177. Automatic exchange systems. TELEFONAKTIEBOLAGET L.M. ERICSSON. 9 Nov., 1966 [9 Nov., 1965], No. 50335/66. Heading H4K. In a directory number/equipment number translator utilizing an arrangement of ring cores through a selection of which each line's test wire is threaded in a unique manner, some of the test wires thread additional cores which denote special services in respect of the associated lines. The service described is a call diversion facility which may involve either diversion of calls to an operator's position where the wanted number is displayed on a lamp panel or automatic diversion of calls to a particular party. The "translating" cores may be of the non-remanent type (Fig. 1) or of the squareloop type (Fig. 2, not shown), the method of reading and writing of the latter being marginally different from the former, but the "service-indication" cores are always of the square-loop type. The translator is similar to that described in Specification 1,178,890. Translator ANL (Fig. 1).-This comprises a distribution frame MK whose inlets L1 to LM represent directory numbers and whose outlets T1 to TN represent equipment numbers. Each inlet and outlet has two appearances on the frame, those on the inlet side being connected to "wipers" X1 and Y1, respectively, of selector V and those on the outlet side to "special service" cores, e.g. e<SP>1</SP>1 and e1, respectively. Each core associated with the outlet appearances, e.g. T1, represents a different service. The test wire from T1 through core e1 is threaded through a selection of the cores gl-v and is connected to a common wire extending to positive battery in a pulse generator PG. Whenever an interrogate pulse passes through one of the test wires, output signals indicative of the required equipment number, are produced on a selection of the wires ta-tv with consequent setting of bi-stable circuits VK1-VKp in a recorder AK. Output signals on wires te, te<SP>1</SP> denote what, if any, special services are associated with the test wire being interrogated. The test wire from T1 through core e<SP>1</SP>1 may also be threaded through an array of translation cores (not shown) in order to provide an automatic diversion facility to a party other than the operator. Outgoing call.-If PBX subscriber A1 initiates such a call by dialling 0, his initial connection via selectors SLA &c. and local junctor SNR to register REG6 is broken down and a new connection to an outgoing line FLU is set up. Incoming calls on lines FL1 are directed to an operator OP who sets up the wanted party's number in her register REG0 The remaining operations then occur as for a local call (see below). Local call.-When the wanted party's number has been inserted in register REGL (or REG0 if an incoming call is involved), a free signal repeater DM is seized. The latter sets selector V to that inlet (L1-LM) of distribution frame MK which corresponds to the registered directory number and also sets rotary selector or relay chain CV so as to complete a path between a pulse generator PG and selector V. Relay R1 in generator PG is brought up via wiper k of CV and consequently interrogating pulses via wipers X1, Y1 are applied to the translator during the charging times of capacitors C1 and C2. The conditions of bi-stable circuits VK1- VKp are then relayed to the register via repeater DM. If one of the cores el or e<SP>1</SP>l is magnetized, as an indication of special service for this line, then one of bi-stable circuits OK<SP>1</SP> or OK is set. Consequently the repeater DM causes the directory number of the called party to be displayed on the operator's lamp panel (connection over wipers Z of selector V) and connects the calling party to the operator over line FO. In addition the set bi-stable circuit OK<SP>1</SP> or OK brings-up relay R22 or R21 whereby a writing pulse is passed through the translator in the opposite direction to that of the interrogating pulse so as to reset the activated cores e1 and e<SP>1</SP>1. The translator, pulse generator and signal repeater are then released. The call proceeds under the control of the operator who inserts the number of the alternative party in her register REGO whereby the above operations, except for the operation of OK, OK<SP>1</SP>, occur. The call is completed finally under the control of the equipment number supplied to REGL and a marker SLM. In order to magnetize or demagnetize the cores e1 e<SP>1</SP>1 the operator dials special prefix digits and then inserts the number of the party from whom calls are to be diverted into her register. The repeater responds to the prefix digits by operating a relay R21 or R31 with R1 whereby the required effects on the cores are obtained. If the system is fully automatic in that the identity of a line is recorded in the register whenever the line is in a calling condition, the subscriber can initiate the diversion facility merely by dialling the prefix digits, the equipment number of the alternative party being preset on the "translation" cores associated with core e<SP>1</SP>1. For a temporary removal of the diversion facility, the operator actuates keys 41, 42 whereby bistable circuits OK, OK<SP>1</SP> are rendered inoperative. Translator (second embodiment, Fig. 2, not shown). This differs mainly in that square-loop cores are used throughout, each directory number and equipment number only has one appearance on the frame and all the special service cores of a line are threaded by the single test wire of that line. Setting or resetting of the special service cores is effected from the signal repeater without any intervention from the pulse generator (see below). Capacitors are used for controlling the emission of pulses through the translator and also (C2, Fig. 2, not shown) for temporarily energizing one of the relays used during an interrogation process.