Old telephones, Candlestick and non-British phones

These telephones may be rung if you can connect a 431A line cord to the telephone (BT style plug to forked leads).

E.g. You need to identify the line in pair of wires or terminals in the phone. This may be achieved if you use an ohmmeter, look for a high resistance reading (open circuit) with the receiver on the rest. When the receiver is lifted a low resistance reading should be obtained. Connect to these terminals the 2 wires of the line cord, which correspond with pins 2,5, of the BT plug.

Candlestick phones require a different arrangement since they do not have an integral bell. Make the connections to these as above. Then either plug into the spare socket another phone, which has an integral bell, or connect an old GPO a/c bell to a 431a line cord, using the 2 wires, which correspond with pins 3,5, of the BT plug. (Plugs are numbered 1 to 6 starting from the plastic locking lever). 3m 431A line cords are available from Precision Vision at a cost of £5.00 each.

For US phones pins 3,4 [red green] of the RJ11 jack correspond to pins 2,5 of the BT431A jack. An RJ11 to BT431A adapter can be provided, free on request.

Caution there is a shock hazard from the ringing voltage of 120v ac.