Patent GB-373177-A (GB)
Title: Improvements in or relating to telephone or like systems
IPC: H04M3/22
Filed: 1931-02-18
Abstract: 373,177. Automatic exchange systems. AUTOMATIC ELECTRIC CO., Ltd., Stiowger Works, and CASWELL, A. E., Ingleside, Milton Road, Edge Lane, both :n Liverpool. Feb. 18, 1931, No. 5197. [Class 40 (iv).] Bi - directional switches are used as distributers and access switches in a routine tester. A relay group individual to a distributer is used to control the access switches seized over its wipers, these latter switches having no relays and using cam springs, off-normals, and magnet contacts to co-operate with the distributer relays. A single indicator lamp group is provided, the lamps being employed successively to indicate different data and thus to identify the particular piece of apparatus being tested. Specifications 340,308 and 346,932 are referred to. Normal operation. The start key STK and the progressive routine test key PGR are depressed. ST operates and locks independently of STK and this key, which is of the non-locking type,releases. The distributer switch vertical magnet DVM energizes over conductor 11 and steps the switch to its first level, GA pulls up breaking the start circuit and extending this circuit through its left. hand winding. All unequipped levels have their vertical bank contacts connected with conductor 15 and assuming the first level is nuequipped earth on DVW is connected to 15 to short GA and prevent HA from pulling up. GA releases, recompleting the circuit for DVM and the switch moves to the next level. GA and DVM interact until an equipped level is reached whereupon HA pulls up to battery on YA and locks. GA releases and the circuit 11 is extended to the distributer rotary magnet DRM. Unequipped rotary positions in the bank wiped by 3a are connected to 17 and when 3a engages such terminals GB, which operated when DRM pulled up, is shorted and releases. GB and DRM thus interact, in a manner similar to that described for GA and DVM, until an equipped position is reached when GB remains up and HB operates and locks. GB releases and the circuit 11 is extended over 1a to the vertical magnet AVM of the access switch. Unequipped levels on the access switch are connected to 15 as were the unequipped levels on the distributer and consequently GA and AVM interact to step the access switch to the first equipped level when HC operates and locks, releasing GA and extending 11 over 2a to the rotary magnet ARM. ARM and GB interact until an equipped terminal is found when HD pulls up and locks. HD breaks the circuit of GB and extends battery over YC and test start conductor 14 to the routine tester to initiate the test cycle. The test conditions are extended over other wipers (not shown) of the distributer and access switches. When the test cycle has finished, earth is extended over conductor 23 to operate test-finished relay TF, Fig. 2. Relay HD releases and the start battery is removed from 14 to allow the routiner proper to reset. ARM re-energizes and steps the access switch to the next equipped position when HD re-operates and the test of the next piece of apparatus takes place. When the access switch moves past the last contact terminals, cam springs AS operate and BS and ARZ operate in series. ARZ releases the switch in a rotary direction and HC falls away. When rotary release is complete, BS releases and the circuit of AVM is recompleted to step the access switch to the next level. GA reoperates and if the level is equipped HC reoperates and the circuits are completed for the access switch to move over the level when the cycle is repeated as before described. The top vertical bank contact of the access switch is connected to BA and when this level is reached BA energizes and locks. When cam springs AS operate on this level BS operates in series with AZM and the access switch restores to normal. Moreover as BA and BS are operated HB releases as well as HC and HD and, when BS releases, the drive circuit is extended to the distributer rotary magnet to drive the distributor to the next access switch. Similarly when the distributer switch reaches the last position in a level, cam springs DS operate to release HA and to operate the distributer rotary release magnet DRZ and the switch is moved to the next level. The contact of 1b following the last equipped position is connected to conductor 22 and when the access switch reaches this position, earth from gb4 shorts the start relay ST and this relay releases. All the energized relays release, the switches restore to normal and earth is extended over 27 and 13 to a delayed alarm set which, after a predetermined. time, flashes the routine finished lamp RFL and, if required, operates an audible signal. Special facilities. The operator can interrupt a test and restart the cycle on the same piece of apparatus by operating RSK. This shorts the starting battery on 14 without releasing HD and consequently the access switch positions are not altered. The operation of STO energizes TF whi.ch releases HD to stop the test and move on the apparatus to the next piece of apparatus. The non-stop routine key NSR shorts the start key STK and if this key is operated, ST re-operates at the end of a complete cycle and re-commences the routining operation. Under these circumstances the circuit for the delayed alarm will not be maintained sufficiently long to cause the alarm to operate. Key CRK. prevents the release of HD by TF, and provides a permanent locking circuit for ST ; its operation thus enables a particular piece of apparatus to be continuously routined. Keys STP enable a particular piece of apparatus to be selected, the keys A .. D if operated in that order, controlling the vertical and rotary magnets of the distributer and access switches respectively. The circuits are arranged so that manipulation of the keys other than in the correct order has no effect on the stepping magnets. The release of either key PGR or CRK releases all apparatus and returns it to normal. Indicating arrangements. All equipped vertical and rotary contacts are commoned to cable 30 connecting with 10 indicating lamps of which two, 1 and 10, are shown. The operation of keys IND, A .. D complete circuits to these lamps over DVW, 3a, AVW, and 1b respectively, and consequently the actual piece of apparatus in use can be identified by operating these keys in turn. The 10th contact of AVW is connected to BA which is operated whenever AVW is in the 10th position, and when IND, C is operated, connection to the tenth lamp is completed over ba4 (Fig. 2).