Patent GB-464058-A (GB)
Title: Improvements in impulse repeaters for use in telephone systems
IPC: H04Q1/36
Filed: 1935-10-11
Abstract: 464,058. Automatic exchange systems. AUTOMATIC ELECTRIC CO., Ltd., BEALE, C. E., and RICHARDS, I. T. Oct. 11, 1935, No. 28168. [Class 40 (iv)] In an incoming or out-going repeater which includes a mechanical device of the kind described in Specification 458,095 for storing impulses and repeating them in corrected form, the circuits are such that if release takes place before all the stored impulses have been retransmitted earth is removed from the holding wire to release the operated switches and the repeater is marked busy until the storage device reaches normal. The repeater shown serves as an incoming one with the dotted line connections or as an outgoing one with connections between the points 3 and 5, 4 and 6, 8 and 10. Line relay A connects up release relay B and impulses are repeated to the receiving magnet RM in parallel with relay C, which holds during each train and energizes the marking magnet MM and relays IP, IS. The receiving disc R of the storage device is rotated step-by-step by the receiving magnet RM and carries a lever which is released by the marking magnet MM at the end of each train to project a corresponding pin through a plate P into the path of the sending disc S. When the magnet MM falls back at the end of the first train, relay BY operates over off-normal contact N and short-circuits IP, whereupon IS falls back slowly and connects up the sending magnet SM which pushes the normal stop pin out of the path of the sending disc S and removes the short-circuit about IP. Relays IP, IS therefore reoperate and the magnet SM falls back, allowing the sending disc S to rotate until it strikes the stop pin corresponding to the first digit, during which time impulses are sent over the outgoing loop at springs IMP. Relay IP is again short-circuited, and the magnet SM reoperates momentarily to initiate the sending of the second train of impulses. Relays IP, IS which provide the necessary interdigital pause could be replaced by a mechanical delay device. When all the digits have been retransmitted, the sending disc S catches up the receiving disc R and offnormal contact N opens and releases BY, IP, IS. If the repeater is an incoming one, the response of shunt - field relay D to battery reversal when the called party replies connects up RB which locks to the holding wire, cuts out the transmission bridge and disconnects magnets RM, MM. If the repeater is an outgoing one, RB merely repeats the battery reversal to the calling side of the transmission bridge. In this case, relay C energizes momentarily upon release of the connection and brings up IP to maintain earth on the holding wire for an adequate period for the release of the distant exchange switches. If the calling party hangs up prematurely, C, IP, IS energize in turn and then fall back, earth being removed from the holding wire when C, IP fall back to release the operated switches and being replaced when IS falls back, since BY is still up. The remaining stored digits arc sent into an open circuit and the relapse of BY then frees the repeater. An earth connection to the negative wire as long as BY is up operates a guard relay at the distant end of the junction when the repeater is an incoming one. Holding of BY for an excessive time operates delayed alarm equipment.