Patent GB-1092480-A (GB)
Title: Improvements in or relating to time division multiplex telecommunications exchange systems
IPC: H04Q11/04
Filed: 1966-05-18
Abstract: 1,092,480. Automatic exchange systems. SIEMENS A.G. May 18, 1966 [May 19, 1965], No. 21983/66. Heading H4K. A time division multiplex switching system effects a wide band data connection by allotting to a calling terminal a number of equally-spaced time slots, the modulation of each time slot being held by a corresponding intermediate store from which it is released in a time slot of a corresponding but differently positioned equally-spaced set of time slots seized for the called terminal. Speech connections are set up with the use of a single time slot in each cycle of a highway. As shown, highways M1, M2, have speech terminals TI1 to T1q and T21 to T2n and have data terminals D11 to D1p and D21 to D2m. Each speech terminal has a highway gate, such as S11, while each data terminal has two gates, such as S211, 8212. The highways are connectible over a multiplex gate SK and have access to intermediate storage capacitors C1 to CK over a highway MS. Circulating stores U1, U2 control the highway gates of M1 and M2; similar stores US and UC control the interhighway gates between highways M1 and M2 and highway MS and between highway MS and the stores C1 to CK. A circulating store UK controls the gate between highways M1 and M2. Speech connection between terminals on the same highway involves a calling terminal to intermediate storage capacitor connection in one time slot and a called terminal to the same storage capacitor in a second time slot. Terminals on different highway can be connected terminal to terminal in one time slot if it is free in both highways. Data connections between terminals on the same highway involve two time slots separated by half a multiplex cycle for the calling terminal and a separate such pair for the called terminal, a pair of intermediate capacitors being seized to bridge the tme gap between terminals. Data terminals on separate highways are similarly connected if coincident pairs of time slots are not free to set up a direct interhighway path by way of switch SK. While each data terminal is shown with two gates, each operated by its respective identity circulating in store U1 or U2, a single gate operated by its identity circulating in two time slots will suffice. A single identity can operate a group of gates in sequence so long as the single control path is switched to each gate by a distributer. There can be more than two highways M1 and M2, each highway having an interhighway gate SK between itself and each other highway, Fig. 2, not shown. Highways may be grouped, as in Fig. 3, each group GR1, GR2 having a battery of intermediate stores CK1, CK2, and having access to other groups over intergroup highways such as Z12. Data connections between terminals in different highway groups involve an intermediate storage pair in each group; a connection involving switching a terminal in one group to an intermediate store, switching that store to a store in the other group in another time slot, and switching the store in the other group to the wanted terminal in that group in a third time slot. The switching between intermediate stores over the intergroup highway does not need equally spaced time slots.