SE347378B - - Google Patents

Abstract

1,119,467. Transmission systems. AMP Inc. 20 Feb., 1967 [4 March, 1966; 15 July, 1966], No. 7947/67. Heading G4H. In a signalling system including a transmitting station and a receiving station, the transmitting station includes an encoder capable of transmitting selected codes of a plurality of characteristic calling codes and each receiving station includes a decoder responsive to a selected one of the characteristic calling codes, each calling code comprising a sequence of characters and each character comprising a sequence of pulses. In the embodiment described data is entered into an encoder at the transmitter by means of a keyboard 70 (Fig. 2A) and stored in a shift register 72 comprising a series of bi-stable stages which store a four digit character in a two out of five code. Under the control of an output driver 73 the data in the register 72 is gated serially to a translating device 75 which includes a relay having two coils W1, W2 connected to be alternately operated by a contact c1. Whenever an output pulse from a set stage of the register 72 is received contact c1 switches its position to either energize or de-energize coil W2 and so open or close contact c2 to control the connection of a battery B1 to the transmitter 74. In this way a serial pulse train is fed from the translator 75 to a transmitter 74 where if required and if for example the transmission is by radio link a single frequency tone may be transmitted when a pulse is received by the transmitter 74 with absence of tone when there is no pulse or alternately one frequency may represent a pulse and a second frequency no pulse. In this case suitable filtering means are required at the receiver. A land line transmitter or an optical transmitter may be used, in the latter case the pulses being used to modulate a transducer capable of biasing for example a laser. At the receiver the complement L of the received pulse train L is also generated and the two pulse trains fed to multi-aperture cores 110 (Fig. 8) having selected windings N c and N s linking the cores through major apertures and windings N x linking all the cores through the minor apertures. The N c windings are selectively connected to the leads 114, 115 on which the two pulse trains are received so that when a receiving station receives its characteristic calling code the first core 01 r is switched to its set state by an initial tag bit and the state of this core is transferred to the next core by each successive bit on the leads 114, 115 so that at the end of the four character code an output signal may be received on output loop 116 of the last core 20 r to illuminate a lamp. To facilitate altering the windings of the cores 110 so that the characteristic code of a receiver may be altered the windings may be connected to a plug board assembly (Figs. 11 and 12, not shown).