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Phone Line Identification

Moderator
Moderator
Posts: 25,891
Thanks: 1,195
Fixes: 50
Registered: 14-04-2007

Phone Line Identification

Sorry but I'm still at that age when I have to ask questions so....
How is my telephone line identified in my exchange.
Is it marked with my phone number or it's service ID......
....or maybe colour coded Tongue
I know we have some ex-telecom engineers around Smiley

Customer and Forum Moderator.

3 REPLIES
x47c
Grafter
Posts: 878
Registered: 14-08-2009

Re: Phone Line Identification


no exact idea myself...but, given that phone numbers can now be re-allocated by BT presumably by a software change:
Then I'd suspect that your line is identifed by something like it terminates in the Main Distribution Frames in something like Bay1 Rack7, Column 4 Row 9
Then in the software there is an allocation of your phone number to the said B1_R7_C4_R9 termination.
So when the BT staff want to ID/inspect the physical termination of the line they go and lookup in the software/GUI your telephone number and it gives them the termination point.
I also think they way they ID your line inside a PCP (which is a frightful mess usually) is to put a tone generator/oscillator on your phone termination point in your house and then use a detector to home in on which pair among the few hundred in the PCP is yours.  I'd guess they get the exchange likewise to put an oscillatiing tone on from that end if they need to ID it from the other side.
198kHz
Seasoned Pro
Posts: 3,233
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Registered: 30-07-2008

Re: Phone Line Identification

In ye olden times the MDF 2 wire jumper would run from the Line side to the Multiple (number) side. A 5 wire jumper would run on the Intermediate Distribution Frame (IDF) from the Multiple side to the Equipment side.
Now it's as described by x47c, at least for telephony. AFAIK, when ADSL is provided, the original jumper is recovered, and the Line and Equipment termination points would each have a jumper run to the ADSL equipment.
In the cabinet (PCP), the E (exchange) and D (distribution) termination points are numbered, and records are held showing the allocations to customer lines. In my day (up to 1999), the records were often unreliable, so the maintenance or provision guy would have to resort to tone identification as described by x47c. I have no reason to believe that things are any different now.  Sad
Not young enough to know everything
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Posts: 25,891
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Registered: 14-04-2007

Re: Phone Line Identification

Quote from: x47c
no exact idea myself...but,

The rest of your post would tend to give a lie to that Wink
Thanks guys for detailed answers to my question Smiley
I've used a tone probe kit on a commercial Cat5 and internal phone system and it's worth it's weight in platinum.

Customer and Forum Moderator.