The Telephone RP3771, which is shown to the right, provides for the termination of 10 lines with a single calling lamp and an engaged lamp and gives the same signalling conditions for outgoing calls as the Switchboard RP 3751. It consists basically of a local-battery telephone modified by the addition of a special base unit accommodating two rotary switches, a ringing key and the calling and engaged lamps.
The 10 lines terminate on one switch so that any line may be connected to the telephone. The other switch selects the signalling condition to be applied to the ringing key for outgoing calls.
On receipt of an incoming call an audible signal is received over the loudspeakers (or the station bell). It is then necessary to search for the calling line by rotating the first rotary switch until the call lamp glows. Lifting the handset then extends an earth to the Panel, Speaker, RP 4634 to release the calling condition and light the busy lamps.
For outgoing calls the first rotary switch is switched to the required line; should this be engaged the engaged lamp will glow. If the circuit is disengaged the second rotary switch is set to the appropriate signalling condition and the ringing key operated.
Last revised: May 30, 2010