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Old August 5th 13, 06:35 PM
Dr.Who Dr.Who is offline
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First recorded activity by TelecomsBanter: Aug 2011
Posts: 8

Originally Posted by stoat View Post

I've got two lines coming in which operate on a same number, so if the first line is engaged the remaining phones still ring, I think this is called "Auxillary Working"? Unfortunately I had to relocate the box and despite recording how it was all originally wired up, the second line feature now no longer working.

Does anyone have a wiring diagam or description of how auxillary lines should be wired up correctly?


Aux line working is also known a PBX working and dates from the strowger days. Then numbers were consecutive, with the lower number being the directory number. So if the first number was 63323, on dialling it again with the first line (63323) busy, the selector would move on to 63324 and ring that line if free, or move on again to 63325 and try that. And so on until the last line in the group was reached, then you got the busy tone.

Now with electronic and digital systems the 'moving' on process does not need consecutive numbers, but just ports which can have any old number within the exchange. Indeed there may be no other numbers at all. There no longer has to be. The the lines would then be numbered 63323/1, 63323/2 and so on.

In the existing system with physical numbers, in my example you could dial 63324, or 63325 etc and ring that particular line only (i.e. no hunting). Useful for night service, and for testing. With the line numbered .../1 .../2 etc there is no way to call one particular line in the group.

You don't say what happens when you call the number with the first line engaged. Do you hear ringing tone, or busy tone. Likewise does the second line still work, i.e. get dial tone and connect calls.

There are two possibilities.

1. The auxilliary line is dis. Therefore with the first line in use, you hear ringing tone as the exchange connects to the next line, but the phone does not ring.

2. The line is short, or looped, which would engage it at the exchange. In this case if the first line is in use, you would hear busy tone as the second line is unavailable.

Either short, looped, or dis lines is a wiring error.

Good luck