GB1069094A - Method of transmitting intelligence by means of a time division (time multiplex) system and arrangement for carrying out the method - Google Patents

Abstract

1,069,094. Automatic exchange systems. TAVKOZLESI KUTATO INTEZET. Oct. 31, 1963 [Oct. 31, 1962], No. 43083/63. Heading H4K. In a T.D.M. system each intelligence signal is preceded by a further signal for routing it in the wanted direction. As shown incoming signals on a line such as k are sampled by a corresponding switch 12 to provide signals which are converted to P.C.M. signals r, k at 12. A generator 15k set up at the start of the call emits the coded identity Pf of the wanted line and this is gated out synchronously by a corresponding switch 14. The two are combined at 13 together with a further pulse or pulse group b for heralding the arrival of a destination code. At the outgoing side of the exchange, or another exchange connected to the preceding exchange by the multiplex highway 16, the destination and intelligence signals are separated at 18, the latter signals being demodulated at 19. The destination signals are passed directly and in inverted form to control the appropriate one of the switches 20 1 ... 20 n , whereby the decoded intelligence sample is routed to the appropriate one of the outlets 1 ... f ... n. If the incoming and outgoing lines belong to the same exchange a separate channel 25 may be provided, in which the intelligence signals, uncoded and amplitude modulated, may pass from the incoming to outgoing section of the exchange. The destination signals may also be in the form of amplitude modulated pulses. The destination code transmitters may consist of a tapped delay line the tappings feeding a common output via gates controlled in accordance with the code, Fig. 2 (not shown). Similar devices using waveguides, Figs. 3 and 4 (not shown) may be used. Each of the sets of switches 21 comprises a decoder for each switch which may consist of two delay lines, fed respectively with the code and its inverse, Fig. 5 (not shown). Tappings from the delay lines are taken at points corresponding to the code required for operating the switch and its inverse respectively and the signals so obtained combined, and fed to a threshold device which only passes a signal when all the tappings are contributing, thereby operating the corresponding switch when it receives the correct code. Busy testing, Fig. 7.-Use is made of the existence of the destination codes on the highway 16 to determine if a wanted subscriber is busy. The destination code of the subscriber is set up on switches 78, and the inverse on further switches 79 to open gates 72, 73 according to the code; and further gates 74, 75 according to the inverse. The received codes and their inverses are fed respectively to upper and lower delay lines whose tappings are connected to the respective gates. The gates feed a common output 77. If the appropriate 5-element code arrives, five gates all pass pulses simultaneously, which operates a threshold detector to give a busy indication.