BT Dropwire External Cable

The BT Dropwire External Cable

(The cable coming in from the telegraph pole)

This cable often has Orange, White, Green and Black wires. Usually (but not always) Orange and White are the active pair and go to connections 2 and 5 in the master socket. In some master boxes (such as the type with a removable front section) they go to two connectors marked B and A.

Which way round they are connected usually doesn’t matter but some modems (especially older USA sourced ones) and some answering machines are fussy about polarity, so it’s wise if possible to check the voltage on the line and connect -48V to the Aleg (5) and 0V to the Bleg (2) in the master socket.

If you have underground wiring with a small grey connection box by the door the internal cabling will usually be the same type and colour as the extension cabling.


On June 5th, 2016, posted in: external telephone cable, telephone cable by

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