Patent GB-730784-A (GB)
Title: Improvements in or relating to circuit arrangements for telecommunication installations, particularly for automatic telephone installations
IPC: H04M15/04
Filed: 1952-08-18
Abstract: 730,784. Automatic exchange systems. SIEMENS & HALSKE AKT.-GES. Aug. 18, 1952 [Aug. 18, 1951], No. 20760/52. Class 40 (4). In an arrangement for determining the class (e.g. zone metering group) to which a number (e.g. telephone exchange code) belongs different parts of the number are registered on two switches whose banks are fed with recurring series of pulses, and an arrangement is provided for detecting coincidence between pulses received over the two wipers. The pulses used are timed as shown in Fig. 7, which represents a complete cycle of pulses P(i)1 ... P(xiii)23 during which time the series P1 . . . P23 occurs 13 times each pulse of the latter series coinciding with a pulse of the former series using the same arabic numeral in its designation. The two-motion switches W1, W2, Fig. 5, may be each set in accordance with the first two (or three) and last two digits respectively of a four (or five) digit code. To allocate a zone group to a particular code, the bank terminal of the switch W2 corresponding to the last two digits is connected to a pulse source providing one of the pulses P(i)1 ... P(xiii)23 having a roman numeral indicating the zone group. To the bank terminal of switch W1 corresponding to the first two digits is connected that source of the pulse sources P1 . . . P23 having the same arabic numeral as the pulse applied to the bank of switch W1. A start pulse Ps then steps off the zone switch DZ which is then moved one step by a pulse Pf every time the roman numeral associated with the pulse series P(i)1 ... P(xiii)23 changes, until coincidence is registered between the pulses applied to the bank terminals of the two switches, DZ being then stopped in a position indicating the zone metering group. As described, the vertical movement of the switch W1 may be controlled either by one digit (if greater than 1) or by two digits (the first being 1) wiper a being effective in the first case and wiper b in the second. The switch W2 is also provided with two wipers to cater both for the class of numbers in which the zone group is dependent on the vertical setting only, and for the class where the rotary setting must also be taken into account. The arrangement may be used to control zone metering or to prevent under-privileged subscribers from obtaining access to certain outgoing directions. Detailed description. Pulse supply equipment, Fig. 6. As indicated in Fig. 7, the cam contacts Pz1 ... Pz13 are closed successively and during each closure the cam contacts P1 . . . P23 pass through a cycle of closures. Coincidence circuits connected between pairs of contacts one from each set operate on simultaneous closure of a pair to produce outputs P(i)1 ... P(xiii)23. Cam contacts Pf, Ps and Ph1 .. Ph5 are also closed periodically as indicated in Fig. 7. All of the pulses P(i)1 ... P(xiii)23 may be provided by cam contacts, instead of by the coincidence circuits shown in Fig. 6. Five digit codes commencing with digit 1, e.g. 14264. Relay C operates on seizure and impulse relay A repeats the first digit to the vertical magnet HM1 of switch W1. Dialling relay V operates during impulsing but not sufficiently long on digit 1 to operate H1, which is made slow to operate by a shunt condenser. As a result the change-over to rotary stepping does not take place when V releases as H2 does not operate. Relay U is operated over decade contact 14dk1 to render wiper b of W1 effective and also to disconnect the action retarding condenser of H1. When the next digit is received W1 is raised a further four steps to the fifth decade. Dialling relay V operates H1 and when V releases H2 operates in series with a holding winding of H1. The next set of two impulses is now repeated to the rotary magnet DM1 which sets W1 to position 52. H1 and H2 release. The next six impulses step W2 vertically and the next four step W2 rotarily to position 64. When the dialling relay releases for the last time start relay St operates to allow the next Ps pulse to kick the zone switch DZ off its home position whereafter it is stepped by succeeding Pf pulses until a coincidence between pulses received over the b wipers of W1 and W2 fires tube R÷ to bring up P and P<1> the former stopping DZ. Zone metering signals are then transmitted over contact 52p from a source ZS in accordance with the setting of DZ. In the present case since the respective pulses are P7 arid P(i)7 the coincidence will occur after DZ has been stepped to its first position. On release interaction with relay A first homes DZ and then W2 and W1 which are of the rotary release type. Four- or five-digit codes commencing with 1, discrimination taking place on the fourth digit. If the fourth digit (which sets W2 vertically) is the last code digit the corresponding decade contact 53dk2 is connected to the pulse source P1 which is also connected to contact 52 of bank c of W1. Thus, when V falls back after the dialling of the fourth digit R÷ being pulsed on both grids by P1 fires to operate P momentarily. Since H has been brought up by the vertical off-normal contacts of W2, P operates K3 which renders wiper a of W2 effective. The contacts of any given level of the bank a of W2 are all strapped so that the same pulse from P(i)1 ... P(xiii)23 is applied irrespective of the contact of the decade to which the switch W2 is stepped. In the case of decade 3 the pulse P(ii)7 is applied so that DZ is stepped twice before being stopped by the firing of the coincidence detector valve R÷. Four-digit codes commencing with 1 in which discrimination is effected after three digits, e.g. 1278. As previously described the first three digits set W1 to position 37 after which a pulse Ph5 is applied via lead 5 and bank c of W1 to one side of the coincidence detector R÷ and the same pulse is applied over lead 5<1> to the other side of the detector which fires to operate P momentarily thereby bringing up K3. After W2 has been set DZ is then set as previously described. Three-digit codes not commencing with 1, e.g. 254. Since W1 does not stop on level 1, U does not operate and bank a of W1 is effective. Also the delay time of H1 expires by the time the second impulse of the first digit is received so that H1 operates and is followed by H2 at the end of the digit to cause the second digit to step W2 rotarily to position 25. Pulse Ph3 is connected to the coincidence detector on the one side over bank c of W1 and on the other side over lead 3<1> and so operates P momentarily to bring up K3. Wiper a of W2 is now effective and zone determination proceeds as in the previous case. Three-digit codes commencing with 1, e.g. 121. W1 is set to position 31 with U up as previously described. Lead 1/2 is supplied with both pulses Ph1 and Ph2 and these are applied over bank c to one side of the coincidence detector the other side of which is connected to Ph1 over 1<1>. The coincidence detector thus momentarily operates P which, with H not yet up, brings up K2. Relay K2 connects the right hand side of the coincidence detector with lead 8 which is fed with all the pulses Pz1 . . . Pz13. K2 also operates St to initiate the stepping of DZ. Contact 31 of bank b of W1 is supplied with pulses Pz13 so that when DZ has stepped thirteen times P operates and stops DZ. Two-digit codes not commencing with 1, e.g. 31. W1 is set to position 31 with U unoperated and R÷ is fired by coincidence of pulses Ph2. With contact 31 of bank a of W1 being fed by pulses Pz10, DZ is stepped 10 times in a similar manner to that of the previous case. Unallocated codes, and detection of faulty tube. In either case R÷ does not fire and DZ steps to position 15 where the normallyoperated relay AL is released by differential action and applies a test striking potential Psp to both sides of R÷. If the test is successful and R÷ fires AL re-operates and DZ steps home. Otherwise the continued release of AL gives rise to an alarm signal and DZ remains on position 15 until AL is re-operated by the handoperated contact T. Statistical metering. Relay P<1> only operates if P operates after St. Terminal 14 is thus pulsed every time a zone determination is made. Terminal 11 is pulsed every time P<1> operates with AL released, i.e. every time a non-existent exchange code is registered. Terminal 12 is pulsed every time AL and P<1> are simultaneously released, i.e. every time there is a failure of valve R÷. A simplified system is also described in which only two digits are used for an exchange code, each digit being registered on a corresponding one of two unimotional switches. The terminals of the switch bank dz2 are provided directly with metering pulses whose frequency is proportional to the rate for the call.