GB555185A - Telegraph system - Google Patents

Abstract

555,185. Telegraphy. STANDARD TELEPHONES & CABLES, Ltd. Nov. 6, 1942, No. 15702. Convention date, Nov. 12, 1941. [Class 40 (iii)] In a telegraph system, any line may be connected to all the others through a single repeater. Fig. I shows the line repeaters A, B, C of three lines connected to transmit to, or receive from, a single repeater R. Each line repeater is asso- :iated with three relays, e.g. A<SP>1</SP>, A<SP>2</SP>, A<SP>3</SP>. A message received by the line relay RR or repeater A is say, repeated over wires 1, 2 to relay A<SP>1</SP> which repeats it over wire 5 to repeater R which in turn repeats it over wire 7 to the relays B<SP>2</SP>, C<SP>2</SP> of all other lines. Relays B<SP>2</SP>, C<SP>2</SP> repeat the message over lines 9 to the sending relays SR of line repeaters B, C and thence to lines B, C. The relay RR of line A also energizes relay A3, which locks up over contacts of relays B<SP>3</SP>, C3 and disconnects relay A<SP>2</SP> from the repeater R so that the message is not transmitted back to the calling line. While A is transmitting to B or C, either of these stations, say B, may break in by sending a prolonged spacing current which causes relay RR of line repeater B to energize relay B<SP>1</SP> to send a prolonged spacing current to station A. Relay RR also energizes relay B3 which opens the locking circuit of relay A3. In another system, Fig. 2 (not shown), having four lines, the contacts of relays RR, A<SP>2</SP> &c. are connected to positive and negative battery instead of to battery and earth as in Fig. 1.