The telephone system of the British post office. A practical handbook (1901)
Herbert, Thomas Ernest · London, New York, Whittaker and Co. · leaf 79
the receiver back to the left 64 CovneciioftS, hand bottom spring (which we have seen also serves for one side of themicrophone) to the bottom spring of the switch-spring from which westarted. The button upon the telephone when depressed connects thebottom right switch-spring to the top right… … Figure 53. The connections are shown in skeleton (in Figure 53), and the variousparts of the apparatus labelled accordingly. It is usual to hang the telephone upon the lever when not in use.This leaves the call battery always on to the operators peg, but cutsthe primary and secondary circuits. The…
Telephone · Postal service
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