Patent GB-731862-A (GB)
Title: Supervisory arrangement for telecommunications switching systems
IPC: H04M3/52
Filed: 1953-03-11
Abstract: 731,862. Automatic exchange systems. SIEMENS & HALSKE AKT.-GES. March 11, 1953 [March 11, 1952], No. 6760/53. Class 40 (4). A device for determining to which of a predetermined set of classes (e.g. charge zones) an exchange code belongs, gives either an indication of the class, or an indication that the code does not belong to any of the set of classes (i.e. the exchange code is non-existent) and in the event of its failing to give either of these indications gives an alarm. The device is seized from an outgoing selector by earth over terminal 1 which brings up C. Impulses are repeated to relay A over terminal 2. Relay A repeats the first train to the vertical magnet Hw1 of switch W1. Relay V operates during the train and when it releases the normallyoperated relay R releases through the shortcircuiting of its winding (ii) to transfer the impulsing circuit to the rotary magnet Dw1 After the rotary setting by the next train E and U operate to connect up the vertical magnet Hw2 of switch W2. This switch is then set in a similar manner by the next two digits E releasing at the end of the first of these and U after the second. Release of U brings up start relay ST which short-circuits its winding (i) to make it slow to release. The two pulse distributers B1, B2 produce pulses as shown in Fig. 2 the top line being the B2 pulses and the remainder the B1 pulses. Thus the B2 pulses are repeated several times during a B1 cycle - which contains groups of pulses, e.g. P(ii)1 ... P(ii)3 coincident with P1 . . . P3. The group, i.e. (ii) in the above case designates the metering zone. To determine the zoning of an exchange code such as 8592 one of the pulses P1 . . . P3 say P2 is connected to the 85 contact of the bank W1 and the pulse P(iii)2 is connected to contact 92 of W2, (iii) being the designation of the zone to which this exchange code belongs. When the distributer B1 reaches terminal Ps relay S operates to open the operating circuit of St and as successive terminals Pf are reached ZO operates to step the zone switch DZ. At each step of DZ, relay Y releases to pulse the winding (iii) of the slow-release relay St to keep it operated. When the distributer B1 emits the pulse P(iii)2 the gas valve R÷ registers coincidence between the pulses received from the bank contacts of switches W1, W2 and fires to operate P. The latter locks, extinguishes R÷, opens the circuit of ZO to prevent further stepping of DZ, and opens the circuit to terminal 1 to release the device from the outgoing selector. If an exchange code is non-existent, then the terminal of W2 corresponding to the last two digits of the code is connected to the elongated last contact NVZ of the distributer B1 and any one of the pulses P1 . . . P3 is connected to the terminal of W1 corresponding to the first two digits. When the distributer reaches contact NVZ, R÷ fires as before and stops the switch DZ in its last position to bring up a relay AR which breaks down the connection and reverts tone to the calling subscriber by means not shown. Faulty operation. If the device fails to give an indication either of a zone or of the fact that the exchange code is unzoned, after the NVZ pulse a long interval occurs before the next Pf pulse so that Y remains operated sufficiently long for St to release, whereupon the alarm relay AL is brought up. This occurrence may happen on failure of valve R÷. Similar action takes place on failure of a Pf pulse or failure of DZ to step. If, when St operates S fails to operate, e.g. due to failure of the Ps pulse, the thermal relay Th operates to bring up AL which in locking disconnects Th. The device may be cleared by operation of key AL. Specification 730,784 is referred to.