Patent GB-283991-A (GB)
Title: Improvements in telephone systems
IPC: H04M3/32
Filed: 1926-10-14
Abstract: 283,991. Automatic Telephone Manufacturing Co., Ltd., and Ostline, J. E. Oct. 14, 1926. Automatic exchange systems.-A routine testing apparatus for testing first code selectors comprises secondary distributor switches, such as SW4, Fig. 1, to the banks of which the selectors are connected and primary distributor switches SW1 - - SW3, to which the secondary distributors are connected. A shelf of 20 selectors is connected to the 2nd - - 21st contacts in the banks of each secondary distributor. Routining starts on the first selector of the shelf connected to the first second distributor SW4 in the banks of the first primary distributor SW1, and is carried on through that shelf, then in turn through the shelves connected to the other secondary distributors in the banks of the first primary distributor, after which the connections are extended over the last contacts of the banks of the first primary distributor SW1 to the wipers or second primary distributor SW2, and so on. The distributing system may be disconnected from the automatic stepping means, and a particular switch, reached by means of primary and secondary distributor setting keys, continuously routined. The switch is busied between cycles to prevent seizure from normal means of access. Manual testing can be carried out by operating a special key to connect the selectors over the distributors to multiple manual test jacks at the first code selector boards, the selectors being impulsed without taking registers into use. The routiner also comprises a test control switch T, Fig. 5, which steps on after each individual test, a switch TS, Fig. 6, which initiates circuit changes at intervals, sending switch S, Fig. 3, and release timing switch RT, Fig. 4. Relay CR, Fig. 5, is operated for continuous routining; relays SA, SB, Fig. 6, operated singly by the primary distributor key, directly connect the second or third primary distributor to the routining apparatus. Various fault-imitation keys are provided for testing the correct operation of the routiner. Time check relays TC1, TC2 are provided which operate to give an alarm if the routining operation is suspended bv a fault, and are re-set at different periods of the test. TC2 operates during routining, and TC1 during the release of the routining equipment. Lamps BSL show the bay and shelf under test, lamps SL the particular selector under test, and lamps FL the progress of the routining, and, if an alarm is given, the particular fault in question. Conductors PC1 - - PC3, Fig. 6, to which varying rates of earth impulses are connected, are connected up for use in various routining operations. Sequence of routine operations. To initiate routining, key AS, Fig. 2, is operated and switch SW4 is stepped to its second contacts to connect up the first of the first code selectors, Lamp AB1 is lighted to show that shelf AB in bay 1 is being routined, lamp SL1 to indicate the first selector therein and lamp FL1 that routining is about to begin. Switch T moves to its second contacts and lamp FL2 indicates test for busy condition. If the position is unequipped the secondary distributor is stepped on automatically. Switches T, TS move to 3rd and 2nd contacts respectively, and lamp FL3 indicates operation of the loop test on the seized selector. Marginal relays in the loop act in the case of increased current due to crossed lines, while if the current is dangerously increased guard relays also operate over one winding and lock over a high-resistance winding to check fuse-blowing. A wheatstone bridge arrangement may be used instead of the marginal relay. Switch T steps to its 4th contacts (FL4) and tests for earth on the selector RT conductor over wiper 3, switch SW4. On the fifth contacts of T, correct seizure of the A digit switch is tested over conductor KR, Fig. 1, which is connected to one side of the relay K of the selector, energized when an A-digit switch is seized as in Specification 264,557. On the sixth contacts, the timed release of the A-digit switch is tested, lamps FL5 being lighted throughout, while on the seventh contacts of T, the code selector is held with A-digit switch released (FL6). Switch TS now moves to its third contacts and T to its eight contacts, where release of the selector takes place as shown by FL7. The same selector is again seized, the lighting of FL8 over the ninth contacts indicating the seizure of an A -digit switch and in the 10th position of T (FL9) the A- digit switch operates to seize a registercontroller, by means of impulses sent by switch SS in passing to its 4th position. Forced release of controller and A-digit switch takes place with T in 11th position (FL10), after which TS and T pass to fourth and twelth positions and the selector is again released (FLU). In the 13th position of T (FL12) the selector loop is again completed and includes a resistance, and six impulses are sent by switch SS to the A digit switch, while in its 14th position (FL13), two more sets of 6 impulses are sent to the register controller, with a shunt resistance across the selector loop, the switch SS passing to its 25th position; the connection is then extended to a special level of a local selector, which is connected back to the routiner, and in the 15th and 16th positions of T (FL14) the holding of the connection during busy flash or operator hold is tested. Metering is tested in the 17th position of T (FL15). while lamps FL16, FL17 lighted in positions T(18), T(19) indicate quick or slow release respectively, the limits being defined by the stepping of switch RT. If release is within the prescribed limits, T moves on to 20th position (FL18), so that switch RT returns to normal, after which T moves to 21st position, and operates relay TM, Fig. 5, to connect up the next selector and to return switches T, TS, SS to home positions. A similar system comprising two primary distributors only is described in the Provisional Specification. Initiation of automatic routine test. To set the routine apparatus into operation, the exchange attendant operates the automatic routine start key AS, Fig. 2, energizing start relay ST, Fig. 3, over conductor 10, cable C1, and spring AS1. Relay SS then energizes and completes a circuit for relays HA, HB, Fig. 4, from earth at SS7. Key AS also starts the time pulse mechanism and conductor PC1, Fig. 6, sends 40 impulses per minute to two-step relay DQ, Fig. 3, [cable C23, conductors 22, 23, C16, 23, ST7, 24, DQ1, 24, DB1, 25, lower winding of DQ to battery], which operates fully when the impulse is removed. The next impulse operates relay DR over DQ1, completing a circuit for relay DT. Two-step relay DS operates over its lower winding, short-circuiting its upper winding until DR restores at the end of the impulse when DS operates fully. The next impulse again operates DR and magnet DM4 of the secondary distributing switch SW4 operates. Two-step relay DB also operates partially and. when DR restores at the end of the impulse, locks up over both windings, and in conjunction with DR opens the circuit of magnet DM4 so that the switch SW4 steps to its second contacts. Relay DQ is de-energized by the opening of DB1 and opens the impulsing circuit for relay DR, and relay DC energizes over DB5. When the switch SW4 advanced to its 2nd contacts. relay LP, Fig. 4, operated, and lamp SL1, Fig. 2, lighted [earth, LP, 51, SL1, 52, C9, 52, wiper P of SW4, 53, IS4, DM4 (not operated)]. Relay LS energizes over LP1, completing a circuit from earth at DB5 for relay DE, Fig. 3, which locks up, and opening the circuit of DT at armature LS1, which also closes an alternative circuit to hold relay DS. When relay DC operated, it removed earth from the homing banks of switches S, TS. energized time check relay TC2, Fig. 2, over PU2, Fig. 4, to earth at DC4, and relay TK, Fig. 5. Fault lamp FL1 is lighted over wiper T(2). Switch T advances its wipers one step [earth, TK1, wiper T(1), DM7]. and relay PU is momentarily energized over the wiper T(1) to open the holding circuit, previously described, and the stepping circuit of time check relay TC2. The said stepping circuit connects 40 impulses per minute from PC1 to the stepping winding of TC2 over PU1, Fig. 4, ST7, and PM1. The time check relay is therefore released and restarted. Slow release relay TN, Fig. 5, now operates over T(3) to earth at DC1. First code selector busy, faulty, or absent. If the switch is busy, earth on its release trunk conductor is connected over wipers SW4(3), SW1. 73, SA4, Fig. 6, SB4, MB3, 74, CB3, Fig. 4, 75, wiper TS(4), Fig. 6, 76, 77, Fig. 2, TR1, Fig. 5, through polarized relays PP, PN, to the junction of battery- and earth-connected resistances R<2>, R<1>. PP only operates and energizes relay TR, which locks up over the circuit just traced, and cuts out PP. Springs TR1 remove stepping earth from second contact of wiper T(1) and first contact of wiper TS(P1). After relay TC1 gives the alarm, the attendant now operates key CRK, releases key AS, operates key SDSK, re-operates key AS, and releases key CRK, thus stepping the routiner to the next first code selector switch. If a key were provided to disconnect relay DB, the routiner could be advanced to another switch thereby as below. If the position is unequipped, battery potential on the R.T. conductor operates relays PN, TM in turn, so that relay DB is released at TM1, and relay DQ is connected to impulse wire PC1 to advance switch SW4 as before. Switch free. Relay TR being de-energized, earth at TR3 steps switch TS to 2nd contacts over wiper TS(P1) and switch T to 3rd contacts over wiper T(1). Circuits are now completed from the positive and negative code selector lines for testing their condition, over the upper low resistance winding of relay TJ. Fig. 5, TJ2, TQ, TB, battery ; and the lower low-resistance winding of relay TD, TD2, relays TP. TA, earth respectively. Relays TA, TP, and TB, TQ are low resistance relays, TP