Patent GB-307405-A (GB)
Title: Improvements in or relating to telegraph systems
IPC: H04L5/22
Filed: 1927-09-05
Abstract: 307,405. Marks, E. C. R., (Western Union Telegraph Co.). Sept. 5, 1927. Multiple telegraphs; distributer systems.- Recording, receiving or retransmitting is effected in a multiplex system by electromagnetic relays co-operating with distributors in such a way as to ensure the utilization of the full signal period by the apparatus in each channel. Fig. 1 shows a transmitting terminal at which a fast channel tape transmitter 5, 6, 10, and a slow channel tape transmitter 8, 9, 15, working at one quarter of the speed of the other, operate a cable 28 through a distributor 1. The magnets 10, 15, which are controlled by the distributor 14, act to withdraw the feelers from the tapes (not shown), and the tapes subsequently act to set up plus or minus impulses on the contacts 5 or 6 and 8 or 9. The distributor ring 2 contains twenty magnets, the first four-segment groups being alloted to the fast channel and the remaining four-segment group to the slow channel. The first segment of each fast-channel group is a pickup segment and serves to transfer the signal set up at 5, 6 to the appropriate locking armature 21 or 22 and sending armature 26 or 27, while the remaining segments of the group are locking segments and serve to hold on the signal while a fresh one is being set up at 5, 6. In the slow channel a fresh signal set up at 8, 9, by the tape is changed during the period allotted to fast-channel outgoing signals. In each case one current transverses the locking relays 17, 18 and 19, 20, in series, from the + or - terminal to the " split " Œ of the battery, the direction of winding being such that either the positive relays 17, 19, or the negative relays 18, 20, move their armatures' on to the appropriate con. tacts, according to the direction of the current. Biassing windings b serve to break contact in all cases as soon as the energizing current ceases. At the repeater station (Fig. 2, not shown) a somewhat similar arrangement enables the fastchannel message to be relayed while the slowchannel message is taken off on to a local recorder and a fresh slow-channel message is sent on from a local transmitter. At the receiving terminal, Fig. 3, signals from the cable 73 are received on the fast recorder 101 and slow recorder 112 respectively, the distributors 77, 91 being allocated to the fast channel and the distributor 104 to the slow-channel. The incoming signals select one or other of the armatures 75, 76, so as to give positive or negative to the conductor 102. In the fast channel the signals pass to the first or pick-up segments of the four groups (which respectively comprise four, four, four and eight segments) in the fast-channel distributor 77 and so to the storing relays 82, 83, one or other of which moves its armature 86 or 87 on to a positive or negative battery contact. The remaining segments of each group hold on the relay 82 or 83 as the case may be. The auxiliary distributor 91 in the fast channel has four groups of five segments each, the last segment of the fourth group corresponding to the first segment of the first group of the distributor 77. As a. result of this arrangement positive or negative impulses from the fast channel pass at evenly spaced intervals from the armatures 86 or 87 through the first or pick up segments of the four groups of the distributors 91 to the fast-channel recording relays 94, 95 and recorder 101, the current to the recorder being thereafter held on through the remaining segments of each group. The signals of the slow channel pass via the seventeenth or pick-up segment of the distributor 104 to the relay 106, 107 and recorder 112, the relay affected being thereafter held on over the remaining segments for the duration of a complete signal period. Arrangements in which there are different numbers of channels in different sections of the line. The invention may be modified (Fig. 4, not shown) so as to provide a fast and slow channel from a transmitting terminal to an intermediate station, the fast channel being continued to a third (receiving) terminal by a simplex channel in which the impulses are nevertheless evenly spaced, or the diplex section of the line may lie (Fig. 5, not shown) between the intermediate station and the receiving terminal. Modification using condensers instead of storing relays. In a further modification condensers may be used for storing the signals. Fig. 6 shows an intermediate station in which fastchannel signals received on the armatures 200 or 201 are relayed over the cable 220 together with slow-channel signals from the local tape transmitter 210, the impulses being evenly spaced in all channels. Incoming signals in the fast channel are stored in the condenser 205 through the distributor 202 in which only the first segment in each of four five-segment groups is utilized. The stored signals are sent en through the distributor 207 (which has five four-segment groups) to the unbiassed sending-on relays 214, 215, the armatures 216, 217 of which are subsequently restored by current sent through the restoring windings r from the distributor 223, which also resets the slow-channel tape transmitter 210. The slow channel signals are inserted into the outgoing traffic by the distributor 207, of which the first four-segment group is allocated to that channel. Specification 10364/14 is referred to.