Patent GB-529346-A (GB)
Title: Improvements in or relating to telegraph systems
IPC: H04L12/54
Filed: 1939-05-30
Abstract: 529,346. Telegraph exchange systems. STEVENS, A. H. (Western Union Telegraph Co.). May 30, 1939, No. 15895. [Class 40 (iii)] In a telegraph system, the exchange has perforated strip or other means for storing and re-transmitting messages, and means for connecting the storing and re-transmitting units to an outgoing channel, the arrangement permitting two or more such units to be associated at the same time with the same channel, the retransmitting part of such units operating one at a time when the channel becomes idle. Certain re-transmitters may have precedence over the others or they may operate in sequence. Branch lines with start-stop printers may be connected by the exchange operator to similar lines or to outgoing trunks using synchronized multiplex working, and the channels of multiplexed lines may be connected to one another or to branch lines with start-stop printers. Automatic numbering machines, of the kind described in Specification 529,345, may be associated with the outgoing channels, so that each re-transmitted message is prefixed with a code indicating its origin and number. In one system described, Figs. 1, 3, 4, 5, a calling line, Fig. 1 (not shown) is automatically connected to an idle storage and re-transmitting unit R2, TT2, Fig. 3. The operator, noting the destination of the message, inserts the plug MP2 associated with the re-transmitter in a jack J10 associated through cable 104, Figs. 3 and 4, with segments A of distributer TD1 of the desired outgoing channel. Each outgoing channel is normally associated with a local sending position T1A, Fig. 4, and on the completion of the transmission of a message from this local position, the channel is connected to the switchboard if a stored message is waiting to be sent over this channel. Assuming first that a message is being sent from the local position T1A, the perforated tape is prefixed with a special code signal which causes the "baffle" relays 31 ... 35 to close a circuit for relay 40, which locks up and energizes relay 41, thereby disconnecting the transmitter T1A for a short time. Relay 40 also closes a circuit for relay 43, Fig. 5, which connects the numbering machine to the segments A of the distributer TD1. This machine operates as described in Specification 529,345 to transmit the code of the originating station and the number of the message. When the numbering machine has completed its cycle, relay 40 is shortcircuited, whereupon relay 41 connects the transmitter T1A to the segments A of the distributer and the message is sent in the usual way. At the end of the message,. a special code signal causes the "baffle" relays 31...35 to energize relay 97 if a plug such as MP2 has been inserted in any of the jacks J1, J10, or J100 associated with segments A of distributer TD1. Assuming plug MP2 has been inserted in jack J10, relay 97 locks up over lead 98 and contacts 101 of jack J10, and extends cable 104 to the segments A. Relay 97 also closes over lead 105 a circuit for relay 106 associated with jack J10. (If a plug has been inserted in jack J1 or J100 instead of in J10, relay 206 or 306 would have been energized in place of 106, but the connection of lead 105 to these relays is such that relay 106 has precedence over 306, and 306 over 206, so that if plugs are inserted in two or more jacks there is a similar precedence.) The message stored in transmitter TT2 is preceded by a special code signal which causes the baffle relays 131...135 to energize relay 110, which locks up, disconnects relays 103, 203, 303, and energizes relay 43, Fig. 5, of the numbering machine over leads 42, 111. When the numbering machine has finished its cycle, relay 110 is short-circuited and completes the circuit of relay 103, which extends the contacts of transmitter TJ2 over jack J10 and cable 100 to cable 104 and segments A. The message is sent in the usual way, the stepping magnet SM being energized over wire 6 of the cables 100, 104 by contact 90 of the distributer TD1. At the end of the message, a special code signal causes baffle relays 131...135 to close a circuit for relay 107, which locks up, lights lamp 115 to indicate to the operator that the transmission is complete, and de-energizes relay 103, so that cable 104 may be connected to transmitters TT1 or TT3 if either of these is plugged into jack J1 or J100. In a modified system, Figs. 6 and 7 (not shown), the transmitters (equivalent to TT1, TT2, TT3) are rendered operative in a predetermined order by a sequence switch to the contacts of which are connected the relays corresponding to 106, 206, 306. The operation is otherwise closely similar to that of Figs. 3, 4, 5. In a further system, Fig. 2 (not shown), messages may be repeated to either multiplex channels or simplex branch office lines. The connections through the switchboard to multiplex channels may be similar to those shown in Figs. 3, 4, 5, but connections to simplex branch offices are modified, (Figs. 8, 9, not shown), to use a start-stop distributer for sending the starting and stopping impulses to the branch office using start-stop printers. The start-stop distributer is individual to the branch line and takes the place of the multiplex distributer TD1, Fig. 4, otherwise the circuits are generally similar to those of Figs. 3, 4, 5.