Patent GB-1034564-A (GB)
Title: Electrical circuit arrangements including switching units operated by electrical marking signals
IPC: H04Q1/20
Filed: 1964-03-23
Abstract: 1,034,564. Automatic exchange systems. SIEMENS & HALSKE A.G. March 23, 1964 [March 26, 1963], No. 12106/64. Heading H4K. In a marker controlled switching system, the markings supplied by the marker are compared with predetermined correct markings whereby if incorrect markings are present they are cancelled before false operation of a switch occurs. The correct markings may be voltages or currents of a certain magnitude or polarity, or they may be in m out of n code or yet again they may only be applicable to certain switches so that any deviation from these predetermined conditions is detected by a testing arrangement and an alarm signal is given. An alarm is also initiated if markings are applied to a busy switch although means may be provided for overcoming this so as to allow break-in working. In the co-ordinate switch shown in Fig. 2, each cross-point relay is provided with a setting winding 1k11 to 1k43 and a holding winding 11k1 to 11k43 and each c-wire of the horizontal and vertical multiples is provided with a busy relay B1 to B4 and 1B to 3B. In order to operate cross-point k11, say, a marker M energizes relays E1 and 1E, whereby the corresponding contacts e and 1e close, thus completing a circuit for 1k11 between the + and - terminals of central battery 2. After a short interval the cross-point closes, thus bringing up 11k11 and B1, whereby the latter operates its busy contact bl in the testing circuit. If either relay B1 or 1B was operated prior to this operation, however, the corresponding rectifier G1 or 1G conducts during marking and thus triggers the relevant bi-stable circuit L- or L +, whereby an inhibiting potential is applied to gate Tz or Ts to cut off the incorrect marking and an alarm signal is transmitted to the marker via terminals bz or bs so that suitable action can be taken. The marker resets the bi-stable circuit via terminal pz or ps. If the new marking is still faulty, gate U- or U + conducts so as to initiate a further alarm. If more than one relay E1 to E4 or 1E to 3E operate during marking, detectors Mz or Ms, of the type described in Specification 832,588, respond and initiate a similar sequence of events. Fig. 4 depicts a twostage network comprising co-ordinate switches IR11 to 1R22, of which the setting, holding and busying windings and contacts are similar to those of Fig. 2. The busy row contacts of the primary stage are connected to a gate Uz1 while those of the secondary stage are connected to Uz2 and similarly for the busy column contacts. The gates are supplied with an operating potential via terminals z1, z2 such that during any marking sequence only the primary or the secondary gate can be opened by an alarm signal from the busy contacts at any one time (i.e. markings applicable to certain switches only). The detector MZ (or MS) comprises a co-ordinate array of terminals 11 to 22 which are connected to the row wires of the switches and via rectifiers to coincidence circuits PR, PZ as shown. This array corresponds to an array of marking relays E11 to E22 in the marker M. In operation, PR or PZ responds if more than one marking relay operates, thereby triggering L- via OR gate Oz and at the same time transmitting an alarm signal directly to the relevant selector WR or WZ in the marker.