Patent GB-883003-A (GB)
Title: Improvements in or relating to teleprinter signal transmission systems
IPC: H04L1/18
Filed: 1959-04-23
Abstract: 883,003. Telegraph transmission systems. SIEMENS & HALSKE A.G. April 23, 1959 [April 23, 1958], No. 13879/59. Class 40(3). In a teleprinter transmission system including a first and second transmitter located at a first station and a first and second receiver at a second station together with first and second sub-channels located between the first and second stations, switching means is operative in response to first idle signals to make the first sub-channel available for message transmission between the first transmitter and the first receiver and operative in response to second idle signals to make the first sub-channel available for message transmission between the second transmitter and the second receiver, and further switching means is operative in response to the first idle signals to make the second sub-channel available for message transmission between the first transmitter and the first receiver and operative in response to the second idle signals to make the second sub-channel available for message transmission between the second transmitter and the second receiver. in the diagrammatic arrangement shown comprising a multiplex radio link between stations A and B, a channel leading to the transmitter SA is allocated by a distributer HS to a sub-channel distributer US which normally connects the main channel to the transmitters of subscribers A1, A2. Similarly, the traffic received by receiver EA is passed by a main channel distributer HE to a distributer UE which normally allocates the incoming signals to the receiving apparatus of the subscribers A1, A2. The arrangement is described in relation to a system using an equal-ratio 7-unit code derived from a 5-unit code, three of the equal ratio code signals in the 7-unit code forming idle signals α, #, and a signal (RQ) requesting the repetition of a signal which has been erroneously received To indicate the end of a message or a pause in transmission the subscribers A1, A2 transmit the signals α, # respectively, whilst the resumption of message traffic is denoted by the signals #, α respectively. If, for example, the subscriber A2 has temporarily terminated his transmission the all-spacing current is transformed to the 7-unit signal # which is transmitted over the channel to the station B. The circuit US after detecting three successive signals # operates a switch device so that the transmitter of subscriber A1 can utilize both sub-channels through the distributer US. At the distant station B the receiving circuit UE in response to two successive signals # effects the connection of both output channels of the distributer UE to the receiver of the subscriber B1. Similarly, the termination of transmission from the transmitter of subscriber A1 effects transmission of the idle signal ½ from his transmitter, and the receiver circuit UE in response to two signals α switches the output of the two sub-channels of distributor UE to the receiver of the subscriber B2. If the subscriber A1 has the use of both channels and subscriber A2 wishes to transmit, the operation of his call key produces a continuous marking signal which is transmitted as idle signal α. When the device in the transmitter circuit US detects these successive signals α it operates to close the channel U2 to the transmitter of subscriber A1, and at the receiver the reception of two successive signals α for the channel U2 operates switching apparatus to connect this channel to the receiver of the subscriber B2. With neither of the subscribers A1, A2 engaged in message-transmission, idle signals α, # are respectively passed from their subchannels, and if the subscriber A1 wishes to transmit, the operation of his call key causes the idle signal # to be passed to the transmitter, with both sub-channels utilized by subscriber A1, and the reception of the signal # on the U 1 channel operates the circuit UE to allow the printer of the subscriber B1 to respond to the signals on both channels.