Patent GB-794811-A (GB)
Title: Improvements in or relating to multiplex printing telegraph systems
IPC: H04L5/24
Filed: 1955-10-18
Abstract: 794,811. Multiplex telegraph systems. DING- LEY, E. N. Oct. 18, 1955 [Sept. 13, 1955], No. 29711/55. Class 40 (3). In a printing telegraph transmission system incorporating a synchronous n-element per channel per cycle time-division multiplex telegraph equipment adapted to pass start-stop code signals in which a start element and the information elements consist of n + x signal elements (x being a whole number greater than zero), and comprising a number of signal input storage devices to which the n + x signal elements of successive start-stop telegraph signals, but not including the stop elements, are applied, means synchronized with the multiplex equipment extract the elements from the storage devices in groups of n which are passed to the equipment for transmission over the multiplex channel to a terminal where the received signal elements are stored in groups of n elements on devices from which the signal elements are extracted in groups of n + x elements by apparatus which also controls the generation of additional elements which serve to reproduce start-stop telegraph signals each consisting of n + x signal elements with a stop element. The signals from a start-stop transmitter are applied from terminals 601, 602 to a relay K6 whose armature connects + or - to a ring R2 or R3 of a distributer DF1 having an arm (Fig. 6) rotated at 300 r.p.m. and one of its ends held by a stop S2 controlled by a magnet M2. When a start impulse is received from the transmitter and the end A is retained by the stop S2, a positive pulse is applied to ring R2 and via brushes B2, B1A to the rest segment R of ring 1 and through the magnet M2 and a relay K9. A positive pulse applied from ring R5 to ring R4 by brushes B5, B4A is fed from circuit R20, C20 and to socket 322 of TB3 linked to a socket 122 of TB1 having connection to a ring 12 connected by a brush B212, Fig. 7, to a brush B206 engaging a segment A-F or 1-6 and applying the pulse to socket 115 or 116 of terminal board TB1 so that relays K7, K8 attract or repel their armatures. The brush arm, Fig. 7, rotates over the distributer face DF2 at 25 r.p.m. If the pulse came from a segment A-F, the signals elements will pass to ring R3 and via brushes B3, B1B to the segments A ... F of the distributer face DF1 and to the associated capacitors. If the brush of DF2 had been on a segment 1-6, the pulse would have passed via sockets 116, 316 to the relays K7, K8 which would have been oppositely energized and the signals applied over ring R2 and via brushes B2, B1A to segments 1-6 and to the associated capacitors. If the lower end B had been retained by the stop S2, a negative pulse would have been applied from ring segment R6 to ring segment R4 and a negative pulse applied over sockets 322, 122 and the corresponding segment A ... F or 1-6 to produce the appropriate operation of the relays K7, K8. When signals are not being sent from the transmitter, the capacitors connected to segments A ... F and 1-6 are assumed to be discharged, but the arm moving over the distributer face DF2 connects + - + - + alternated with - + - + - from rings 1 to 5 to rings 7-11 and via terminals 117 ... 121 to terminals 317 ... 321 connected to relays K1 ... K5. The relay K1 will receive alternate negative and positive pulses over brushes B201, B207 and sockets 117, 317 and relays K2 ... K5 will be similarly operated over rings 2, 3, 4, 5 of DF2 and the associated socket pairs 118, 318 ... 121, 321. The operation of relays K1 ... K5 will pass the appropriate five unit elements, each of 10 msecs. duration, to the terminals 501 ... 505 of the transmitting end of the multiplex line. At the receiving end the five-unit signals are passed from the sockets 701 ... 705 of the multiplex line to sockets 417 ... 421, 217 ... 221 connected by brushes B208 ... B212 to brushes B202 ... B207 of the brush arm, Fig. 7, rotating at 25 r.p.m., which pass the pulses to the radially disposed segments 1 ... 6, A ... F in the rings 2 to 6 of distributer DF3 and to the appropriate capacitors associated with terminals 401 ... 412. The segments 1 ... 6, A ... F are displaced by a distance corresponding to 10 msecs. Capacitors with segments 1, 3, 5, A, C, E receive only negative charges and the capacitors associated with segments 2, 4, 6, B, D, F are always positively charged. The corresponding segments in the groups 1 M, A ... M formed in the outer ring, which are of length corresponding to 8 msecs. and are 22 msecs. apart, receive the appropriate charges and are discharged by a seventh ring having segments S which are connected by brush B207 and discharge segments 1, A, M to terminal 214 connected with terminal 414 controlling relays K11, K13, whilst the pulses from segments 2 ... 6 and B ... F are passed through sockets 215, 415 to relays K12, K14. If it is assumed that a letter, e.g. Y, is to be transmitted and that the brush of the arm rotating over the face DF2 is in engagement with a segment A-F, the relays K1, K2, K3 will be in the spacing marking, spacing positions respectively since segments 4, 5, 6 have not received any charge from the distributer DF1. The relay K4 will receive the start pulse of the character from segment A and change to the spacing position, whilst the relay K5 will receive from element B the first code element of the letter Y and change to marking. The elements as determined by the relays K1 ... K5 will be transmitted over the multiplex line, and the relays K1 ... K5 will be temporarily reset to - + - + by the segments prior to those marked C, D, E, F, 1. Later the second code element of the letter Y appearing on segment C will reset K1 to space and the 3rd, 4th and 5th elements on segments D, E, F will set the relays K2, K3, K4 to marking, spacing, marking respectively: The fifth relay will be set according to the first element of the next signal and these elements are transmitted before relays K1 ... K5 are reset to + - + - + prior to the continuation of the signal which has followed the letter Y. At the receiving end of the multiplex channel, these impulses are applied by the rotating brush to segments A, B of one radial set and C, D, E, F of the subsequent set and are also set up on the segments A, B, C, D, E, F of the groups of the outer ring from which the pulses corresponding to the A and M segments are passed by the S segment of ring 7 and sockets 214, 414 to the relays K11, K13 and the elements from B, C, D, E, F are passed to relays K12, K14. A negative pulse from segment M energizes K11, K13 so that the output circuit is closed, but the positive start pulse from segment 1 or A releases relays K11, K12 so that the five-unit output signal preceded and followed respectively by start and stop signal elements are passed to the terminals 801, 802 leading to a teleprinter. In response to the transmission of the idletime signal and its reception in the form MSMSM, SMSMS, MSMSM, SMSMS ... the elements, indicated by underlining, passed to the segments 1, A will always be marks, and over segments S of ring 7, the relay K11 will be energized, lock up and operate relay K13 to close the circuit to the output terminals 801, 802. The operation of relays K12, K13 in response to the alternatives of M and S will be without effect, and the marking condition on the output line to the teleprinter will be maintained for 240 msecs. until the period of a subsequent start element. Specifications 670,758, 670,759, 670,762 and 794,522 are referred to.