Patent GB-196879-A (GB)
Title: Improvements in telegraph systems
IPC: H04L25/04
Filed: 1922-07-11
Abstract: 196,879. Western Union Telegraph Co., (Assignees of Peterman, W. C.). April 28, 1922, [Convention date]. Repeating systems using contactmaking relays; restoring or modifying imperfect signats; perforated strip transmitters.-Relates to repeating systems, particularly for submarine cables, in which rotary distributors co-operate with receiving, storing and transmitting relays. The duration of the repeated impulses may be varied, and block signals may be broken up into their component parts of any desired length. In one modification, two sets of receiving and storing relays are used alternately. An automatic transmitting system using similar storing relays and rotary distributors is also described. In the repeating system shown in Fig. 1, positive and negative impulses cause a drum relay 25 to energize the dot and dash relays 27, 28, respectively. Assuming that relay 27 is energized when the brush 41 of the distributor engages " pick up " contact p, current flows from the negative pole of battery 30 over the armature of relay 27, wire 31, contact p, brush 41, wire 50, and polarised relays 52, 53 to the middle point of the battery. The dot relay 52 energizes and when the brush 41 engages the next contact l, a circuit is closed from the negative pole of battery 30, armature of relay 52, dot transmitting relay 62, contact l, brush 41, and relays 52, 53 to battery. The storing relay 52 is locked in this circuit until brush 41 leaves the contacts l, and by varying the number of contacts l strapped together the duration of the re-transmitted impulse may be adjusted. In a similar way, if relay 28 is energized the positive pole of battery 30 is connected to relays 52, 53, relay 53 energizing the dash transmitting relay 63. In a modified system in which the re-transmitted impulse may have a period equal to the full unit time of a code impulse, the transmitting relays 62, 63 are included in the energizing circuit, as well as in the locking circuit of the storing relays 52, 53. In a further system shown in Fig. 3, two pairsof storing relays 52, 53 and 52<1>, 53<1>, are used alternately to control the transmitting relays 62,. 63. Assuming that the distributor brushes 65, 66, 67 move downwards from the position shown, the cycle of operations is as follows :-(1) brush 65 closes a circuit through the re-setting windings r of the storing relays 52, 53; (2) brush 66 sends current through the transmitting relays 62, 63 in one direction or the other according to which of the storing relays 52', 53<1> was energized by the last impulse; (3) bush 67 closes a circuit through the energizing winding e of the storing relay 52 or 53 and the marking contact of the receiving relay 28 or 27; (4) brush 65 closes a circuit through the re-setting windings of relays 52<1>, 53<1>; (5) brush 66 brings the transmitting relays 62, 63 under control of the storing relays 52 or 53; and (6) brush 67 brings the. storing relays 52<1>, 53<1> under control of the receiving relays 27, 28. In the automatic transmitting system shown in Fig. 4, two pairs of storing relays 102, 103 and 104, 105 are set by the perforated strip 37 and control the transmitting relays 130, 131. The cycle of operations is as follows :-(1) The brush 120 energizes the re-setting windings r of the storing relays 102, 103; (2) brush 119 closes a circuit through the transmitting relays 130, 131 in one direction or the other according to which of the storing relays 104, 105 was energized by the last impulse; (3) brush 118 closes a circuit to energize the storing relay 102 or 103 according to which of the contacts 36 or 35 has been closed by the strip 37; (4) brush 120 re-sets the storing relays 104, 105; (5) brush 119 brings the transmitting relays 130, 131 under control of the storing relay 102 or 103; and (6) brush 118 brings the storing relays 104, 105 under control of the strip-controlled contacts 35, 36. The perforated strip is fed by the motor PW driving the distributor. The duration of the transmitted impulses is determined by the number of contacts of the transmitter ring which are strapped together. If both pins strike an unperforated section of tape, the cable is earthed. Synchronous movements and synchronism indicators.-At each reversal of current in the cable, or at each dot impulse, the corrector relay CL, Fig. 1, closes a circuit through slow-acting relay R b and, if the distributor is not svnchronous with the incoming impulses, over the armature of relay Rb, brush 40, synchronizing contacts of the ring 35, to energize relay Ra. The relay Rb opens this circuit a moment later, but the quick-acting relay Ra locks up, energizes the magnet m of a mechanical phase corrector, and closes the circuit of a slow-acting relay Rc, which short-circuits relay Ra, thus de-energizing this relay and magnet m. Synchronizing lamps L are connected through groups of contacts on ring 37 and a switch 33 to the front contact of the corrector relay CL. The instant of change from one impulse to the next can be noted bv observing which of the lamps is first lighted and the brushes 40, 41, 42 are then moved until the change occurs when brush 42 is on the first of a group of contacts. Specification 196,980 is referred to.