Patent GB-585203-A (GB)
Title: Improvements relating to the selective marking of selecting and counting switches
IPC: H04Q3/42
Filed: 1945-02-08
Abstract: 585,203. Automatic exchange systems. SIEMENS BROS. & CO., Ltd., and LONG, D. P. Feb. 8, 1945, No. 3179. [Class 40 (iv)] In an arrangement for controlling the setting of a switch by markings applied by relay or key contacts which are operated singly or in combinations, the number of contacts required is reduced by the provision of a marking bank and a guarding bank which are so arranged that when a particular contact marks several terminals in the marking bank the connections to the guarding bank prevent the operation of the test relay in earlier positions when a later one is .to be selected. In Fig. 1, ten markings are provided by four relays which may be operated by impulses as described in Specification 471,987 or by keys. The test circuit runs from earth over an operated change-over contact w, x, y, z and marking bank M through test relay T and guarding bank G to battery and, if the switch is to stop on a later contact of those marked by any relay, the test relay is prevented from operating in earlier positions by shunts over unoperated change-over contacts. A similar arrangement in which battery is connected to the wiper of the guarding bank is described with reference to Fig. 2 (not shown). In Fig. 3 (not shown), undesired operation of the test relay is again prevented by shunting, but the marking bank is connected to the centre spring of change-over contacts and in Fig. 4 (not shown) a shunt system employs simple make contacts with battery connected to the wiper of the guarding bank. Fig. 5 shows a series arrangement in which the test relay T is prevented from operating on undesired contacts by having its circuit broken by a series guarding contact x, y, z. This method involves additional relay contacts for breaking the test circuit. The application of the invention to a register controller of the type described in Specification 573,885 is shown in Fig. 6, this providing four registers for thousands, hundreds, tens and units digits, of which the hundreds and tens registers HR, TR are employed also for the two code digits and the units register UR also performs distributing functions. The codetranslating switch, which by the use of doubleended wipers provides 104 positions, has marking and guarding banks M, G and is set in succession in accordance with the two code digits, stopping positions 2, 12, 22, &c. being marked from the hundreds register and the individual positions between the stopping positions being marked from the tens register, the connections being similar to those in Fig. 3 (not shown). The higher denominational registers operate similarly to the units register UR and only this register is shown in detail. When the register is seized, line relay A and release relay B (windings not shown) operate and discharge condenser QG and on receipt of the first impulse AX operates on the charging current of QG. The first counting relay HW of the hundreds register operates in series with the opposing winding of AX and locks while AX releases. Subsequent impulses of the first code digit operate the hundreds counting relays in the manner described in Specification 471,987. On the relapse of dialling relay C at the end of the digit, CX operates and connects up UW, which directs the next digit to the tons register and starts the code switch in search of the marking provided by the hundreds register contacts hw &c., the switch being stopped by the operation of T. Relay UX operates at the end of the second code digit and connects up MC which, if this digit is other than 1, releases T and restarts the code switch to find the marking provided by the tens register ; after which T re-operates and connects up MT. If the second code digit is 1, however, T is held over tz7, tw7 upon operation of MC and MT pulls up at once, without further movement of the switch. The hundreds and tens registers are now released and the various registers are set in succession by the numerical digits.