Shared Knowledge


Telephone Cables


22 February 2008




 Summary: most telephone extension cables sold today have 4 wires in them. Older cables only have 2 wires. If you are having problems getting a telephone to work, dump your old 2 wire cable for a modern 4 wire.



If you are having a problem with a 2-line telephone or even a single line telephone, check the cable between the telephone device and the telephone jack. Once upon a time, telephone cables only came with 2 wires in them or good enough for only one phone.


To get a 2-line telephone to operate you must use a cable between the device and the wall jack that has 4 wires in it. To confirm you have a 4 wire cable, look at one of the male connectors and you should see 4 gold-color metal tabs in it that make contact with 4 wires in the telephone jack when the cable is inserted.


Problem with a single line telephone? There is a “standard” as to how telephone wall jacks are wired for 2 or 3 telephone lines (newer homes actually have a 6 wire telephone cable run in walls) but who ever wired the jack might not have followed the standard and if you are unlucky enough to have picked up only a 2 wire telephone to jack cable, it is possible your telephone is sitting on the wires in the jack meant for line 2 which you do not use. Using a 4 wire cable should correct this problem.


After running into the 2 wire telephone cable problem more than once, I now just throw all 2 wire telephone cables away I find.