Relay LS cannot, therefore, be operated over the station line loop and thus is connected to earth at the exchange by strapping changes on the relay-set shelf jack. ... As the wipers step from contact to contact the P-wire of each outlet is tested to determine whether or not it is free, ... At the end of its delay, relay G operates.
|Title||:||Telex: a detailed exposition of the telex system of the British Post Office|
|Author||:||Roy Worth Barton|
|Publisher||:||Pitman Publishing - 1968|