We were operating by pure feel in the total darkness where balancing alone was precariously.
Operating mistakes also cause interruptions to conversations, as it is possible, by the insertion of a plug in a multiple jack, to disconnect the circuit between two talking subscribers.
This alteration improved the operating conditions in three ways.
The conditions permit of the circulation of the alternating currents of low periodicity, which are used for operating the bells, but in respect of the battery the circuit is open until the subscriber lifts the receiver, when the hook switch, thus released, joins the transmitter with one winding of an induction coil in series across the circuit.
The Postmaster-General also agreed to lay underground wires for the company at an annual rental of L1 per mile of double wire in any local area in which the company was operating, but not in areas in which the municipalities had established exchanges.