Patent GB-439778-A (GB)
Title: Improvements in or relating to telephone and telegraph signalling systems
IPC: H04M11/06
Filed: 1935-04-08
Abstract: 439,778. Exchange systems. KLEINSCHMIDT, E. E., 2620, Deere Park Drive, Highland Park, Illinois, U.S.A. April 8, 1935, No. 10868. Convention date, April 14, 1934. [Class 40 (iv)] In a combined telephone and telegraph system, the telephone and telegraph sets of a subscriber, connected to the exchange by a single line, each have a corresponding line switch which respectively gives access to jacks for extension of telephone calls by operators, and to telegraph receivers, the arrangements being such that both line equipments are busied when either set is in use. In the system described, telephone and telegraph calls to the substation are set up by operators over separate jacks or automatically over separate connectors. Outgoing telephone call. Removal of the receiver at the telephone equipment 2 disconnects the ground at 33 which, as will appear later, is required to enable the sub-station telegraph equipment 1 to obtain access to the line and lock out the telephone equipment. Line relay 53 pulls up, but differential relay 71 also connected in the loop remains inert. Magnet 52 steps line-switch 50 until an idle jack 60 is found and cut-off relay 54 operates, whereupon relays 61, 62 pull up, lamp 63 lights and an operator responds and extends the connection. Outgoing telegraph call. Key 19 is depressed and held by latch 20, and a calling circuit is made from ground 33 at the telephone set, line wire 44, diiterential relay 71 (lower), and line relay 53. Relay 71 operates, holds, cuts off the line relay and operates line relay 75 of the telegraph line-switch 72 in a circuit from ground at 33, polarized magnet 21, relay 15, contacts of relay 18 energized by key 19 from a source at 35, magnet 12 and line wire 11. Magnets 12 and 21 remain inert but. relay 15 pulls up, opens the telephone loop, connects up a ground to replace that from. the telephone set and starts up motor 14. Line switch 72 hunts for a telegraph recorder, cut-off relay 76 operates relay 82 followed by 83 which holds 82 locally. Relay 82 completes the telegraph circuit from magnet 85 over wire 11, sub-station magnet 12 and polarized magnet 21 in which magnet 21 operates to release key 19 in view of the polarity of battery 90. Relay 18 relapses to remove the shunt on the transmitter 13 and the circuit is ready for use. During use for outgoing telegraphy the ground on wire 91 busies telephone exchange equipment 5, 6 and telegraph equipment 9, 10 for incoming calls, and partially operates cut-off relay 54 (interlocked with un-operated line relay 53) so that its back contacts are opened. The telegraph connection is released by sending a code to magnet 85 whereby pull bar 87 closes contacts 88 to operate 84 which releases 82, 83 and then relapses slowly. In the meantime, 84 maintains the busy marking on the various equipments, and relays 76 and 54 remain energized. The opening of line 11 releases 15 at the substation which disconnects motor 14. Incoming telephone call. The line may be seized and rung by a connector 6 or by an operator over plug and jack 100, 101. Ground on the third wire partially operates the cut-off relays 54, 76 which open their back contacts to prevent outgoing telephone or telegraph equipment from being operated. Incoming telegraph call. The plugging of jack 110 by an operator completes a ringing circuit from generator 114 over line 11, magnet 12, A.C. relay 17, key 19 to ground at 33 in the telephone set. Relay 17 responds and completes a D.C. circuit from reversed battery 120 over the exchange telegraph transmitter 116, receiving magnet 115, relay 112 (upper), line 11, receiving magnet 12, transmitter 13, relay 15 to ground at 33. Relay 15 pulls up, disconnects the telephone set, starts the motor 14 and when this has speeded up centrifugal switch 24 shunts resistance 25 so that 112 at the exchange pulls up, locks over its lower winding, cuts off the ringing generator and completes the telegraph circuit. Ground at plug 111 busies the various equipments. Distant operators may be connected manually, or as shown, they set up automatic connections over connector 121.