answering cord造句

Early manual switchboards required the operator to operate listening keys and ringing keys, but by the late 1910s and 1920s, advances in switchboard technology led to features which allowed the call to be automatically answered immediately as the operator inserted the answering cord, and ringing would automatically begin as soon as the operator inserted the ringing cord into the called party s jack.
The operator responded by inserting the rear cord ( " answering cord " ) into the subscriber's jack and switched her headset into the circuit to ask, " Number, please ? " For a local call, the operator inserted the front cord of the pair ( " ringing cord " ) into the called party's local jack and started the ringing cycle.
It's difficult to find answering cord in a sentence. 用answering cord造句挺难的