Patent GB-771058-A (GB)
Title: Circuit arrangement for substantially simultaneous transmission of a number of communications through a common transmission path
IPC: H04Q11/04
Filed: 1953-02-02
Abstract: 771,058. Automatic exchange systems. SIEMENS & HALSKE AKT.-GES. Feb. 2, 1953 [March 11, 1952; March 11, 1952], No. 2962/53. Class 40 (4). [Also in Group XL (c)] In a time division multiplex transmission system in which communications from one station to another are transmitted over lines or wireless links as amplitude modulated pulses, each station is allotted a time position in a recurring cycle of time positions corresponding to the channels of the common transmission path, and groups of stations, the spacing of the time positions of which is a multiple of the channel spacing, are each connected by one or more gating and commoning arrangements to the common transmission path, each such arrangement passing only pulses having the time positions of the stations of the corresponding group and simultaneously expanding these pulses. 100-Line exchange, Fig. 2. A subscriber's loop is connected via a hybrid G10 ... G19 to a 4-wire line having go and return gates AT10 ... AT19, ET10 ... ET19. The four-wire lines of subscribers having the same units digit are commoned to group go and return gates AI ... X, EI ... X, and all such gates are connected to the input and output multiplex trunks ME, MA, respectively. Eachsubscriber is allotted a time position 1 Ás. in length in a frame of 100 Ás. When a subscriber Tn11 calls Tn10, pulses P11, of length 5 Ás., and starting in the time position of the caller, pass from the gate AT11 to gate AI to which are applied pulses P11<SP>1</SP> in the caller's time position and of 0.5 Ás. duration. Thus pulses P11<SP>1</SP> appear on the input multiplex trunk and take into use an idle connecting device VE, Fig. 3. When the pulses P11<SP>1</SP> beat with those of an oscillator O1 a phase comparator Phv1 locks the oscillator and opens gates ET1, AT11 to the pulses P11<SP>1</SP> which are passed through a low-pass filter T1 to an arrangement NF1 which in accordance with the dialled signals characterizing the subscriber Tn10 sets a phase shifter Ph allotted by switch Pz to lock oscillator 02 to produce pulses P10<SP>1</SP> in the time position of the called line Tn10 to open gates AT1, ETII. Pulses P10<SP>1</SP> in the time position of the called party appear in the output multiplex trunk MA and are fed to the ten return group gates EI ... EX. The subscriber's pulses such as P10 are applied over a valve RO3, Fig. 4, and a transformer Tr2 to a differentiating circuit C1, Tr3 to produce the pulses such as P10<SP>1</SP> which open gate RO1 to the appropriate pulse on trunk MA. A pulse P10<SP>1</SP> from the cathode of RO1 charges condenser C2 which remains charged until the 5 Ás. pulse P10 applied to rectifier Gl2 ceases. Tube RO2 thus passes pulses P10 which are gated through the return gate ET10 to a low-pass filter TP10 and amplifier. T10 to the called party Tn10. When the called party answers, pulses P10<SP>1</SP> are applied to the input multiplex trunk ME and operate a phase comparator Phv2 which takes over control of the oscillator 02 whereupon the phase shifte Ph is released. The pulses P10<SP>1</SP> pass through gate ETII to a low-pass filter TII which feeds gate ATII to produce pulses P11<SP>1</SP> on the output multiplex trunk MA, which pulses are gated to the caller. Speech modulates the pulses. Pulse supply. The 0.5 Ás. pulses are supplied from a central generator. To obtain the corresponding 5 Ás. pulses the shorter pulses are applied to a tube RO, Fig. 1a, and the resulting cathode pulses charge condensers C1 ... C3 which due to the impedances L1 ... L3 discharge in turn to produce a 5 Ás. output pulse. Alternatively the main generator produces 5 Ás. pulses which are differentiated to form the 0.5 Ás. pulses. 1000 Line exchange, Fig. 6. Each of ten groups G1 ... G10 of 100 subscribers are connected to a pair of multiplex trunks ME1, MA1 ... ME10, MA10 as described above. Each pair of trunks is connected to two horizontal bars W1 ... W8 of a cross-bar switch and also through its connecting device VE to two vertical bars S1 ... S16 of the cross-bar switch. The first digit effects the connecting device VE to close crossing points of the crossbar switch to connect the pairs of multiplex trunks associated with the caller and the called party over the connecting device VE seized by the caller. The remaining digits effect the connecting device as described above to delay the communication pulses so setting up the connection. The cross-bar switch may be replaced by relays ; wiper switches or switches consisting of thermionic or cold cathode tubes.