Patent GB-772267-A (GB)
Title: Improvements in or relating to apparatus for exclusively connecting one of a plurality of circuits with common equipment intended to serve all of said circuits
IPC: H04Q3/00
Filed: 1954-10-26
Abstract: 772,267. Automatic exchange systems. SIEMENS & HALSKE AKT.-GES. Oct. 26, 1954 [Oct. 26,1953], No. 30929/54. Class 40 (4). In an arrangement for associating one of a plurality of equipments with a common equipment two multiple test wires are provided, the first being connected to the second via a resistance Wi9 and thence through a further resistance to earth, each equipment being provided with a test relay P and a test resistance Wi6 to each of which battery is applied when associated equipment is required to use the common equipment, the relay P being connected to the first multiple wire and the test resistance Wi6 being connected to the second multiple wire. The invention is described with reference to the use of a common multiple by a metering-zone determining device. Setting of switches. An incoming line FL on connection to such a device momentarily operates. CFL to bring up C. Incoming digits of which four may be required to determine the zone are repeated by relay EF (not shown) to relay A for registration on unidirectional motordriven switches mw1, mw2, each of which registers two digits. Each switch has two field magnets (M1, M2 and M3, M4, respectively) which are energized in succession through cam contacts (m1, m2 and m3, m4) which are energized alternately. The switches are stopped by energizing both magnets. Each switch has contacts zr which are made at the end of each decade and contacts hr made at the beginning of each decade. When A operates on seizure both magnets of the first switch are energized, M1 over m1 direct and M2 over m1 off-normal contact 4nr1 and contact 14a. On the first impulse the latter circuit opens and the switch is driven to the beginning of the first decade where the latter circuit is closed over contact 20hr1. When A restores the switch is driven to the end of the decade when the switch is again stopped, current for the two magnets being provided directly in the one case and over contact 21zr1 in the other case. Further stepping by decades occurs in a similar manner. Relay V operates during the impulse train and restores at the end of it to bring up relay U. Impulses of the next train now move the switch one step at a time. Thus every time A is up one of the magnets is energized directly over its own contact and the other indirectly via winding (i) of relay D. When A releases during an impulse, the indirect circuit is broken and the direct circuit is maintained via contact 27a so that the switch takes one step whereupon the other magnet becomes energized over its own ml or m2 contact and the switch stops. The holding circuit via 27a is applied alternately to M1 and M2 by relay D which operates on alternate impulses since its winding (i) is arranged to be energized alternately in the same and in the opposite sense to its winding (ii). When V releases at the end of the second impulse train relays O, Oh operate to transfer the impulsing circuit to magnets M3, M4 of the second switch which is set in a similar manner. Zone determination. At the beginning of the third impulse series J and X operate and at the end of the series An operates to commence a test on the multiple in case zone determination can be effected after three digits only. Relay An connects battery to the circuit containing a potentiometer Wi6, Wi8 and to relay P in series with Wi9. If the multiple is not is use P operates. Otherwise if a further zone device VZx is connected, the potential at lower end of resistances Wi6 falls so low as not to be able to operate a plurality of relays P in series with Wi9. A test relay P once operated, however, can be held by the reduced current due to a second device making a slightly later test. Assuming a successful test is made P operates and connects the charged condenser C1 to the wipers of the switches in one case via zone determining relays E1 ... E4. It is here assumed that account must also be taken of the fourth digit so that none of these relays operates at present. When P operates J and X release successively and the test circuit for the multiple is disconnected so that P releases. Relays J and X re-operate at the beginning of the fourth impulse train at the end of which An also operates and the multiple is tested again. If it is free P operates and connects up the condenser Cl as before and according to the crossconnections of the contact-banks mw1, mw2 through the multiple ZF brings up a combination of relays E1 ... E4 indicative of the metering charge. These lock up in series with corresponding relays H. The latter indicate over a contact tree the metering charge, by applying earth to one of leads FZ1 ... 10 for reading off by a scanner agr a relay K connected thereto effecting release of the equipment. If through a fault or because the dialled digits do not correspond to any metering charge, C remains operated to energize the slow-tooperate relay Ab to light a warning lamp or release the connection. If the multiple is busy when a test is to be made P remains unoperated and J remains operated, so that X is shortcircuited and releases, followed by An. Relay X then reoperates and the test is repeated until successful. The relay timings are arranged so that the test period and period of use of the multiple is very short compared with the interval between tests so that in the event of a simultaneous demand two testing arrangements can rapidly get out of step (due to differences, e.g. in the operate times of the An relays). If denial of access to the multiple persists until the next digit is received alarm relay Ab comes up.