Kitz Forum
Broadband Related => Telephony Wiring + Equipment => Topic started by: Weaver on September 07, 2018, 02:31:31 AM
-
A basic ignorant question: say I am out on the wild and windy moor and I need to inspect a copper pair in a bundle. How on earth do I identify the pair?
-
One for Black Sheep I think but Tone and Probe is my answer.
-
You leave a tone generator on at the property and then you test them all?
-
Openreach can identify the correct pair without entering the EU's premises, so it must be recorded by colour coding.
-
In a cable bundle each wire pair is colour coded, and the colour identifies and counts up to the last pair using that code. Only jointers would mess with these cables though.
Inside the DP or PCP (green cab) they are helpfully numbered for normal engineers ;)
-
When there are four pairs entering the EU's premises, how do they identify which pair to investigate to start?
-
Colour coding doesn't mean much on a long D-side rural run of cable. For example, the cable leaving the Cabinet will probably be a 50/100pr .... this in turn will slowly become a lower-capacity cable (1/2/5/7/10/15/20/30pr) as the distance increases and pairs are 'dropped off' at various other DP's.
Therefore, in essence, 'your' circuit could be leaving the Cabinet on a green/white pair of wires and arrive at the premises on a slate/red pair.
So, there are basically two methods we would deploy to identify the End Users pair. One would be to apply a manual tone generator (Otherwise known as an oscillator), or we can apply an 'Auto-tone' from our work i-Phones by using the 17070 facility, which recognises the task we are on and offers up a suite of applications we can use such as remove/apply voltage, remote emulation scripted tests, auto-tones etc ....
With the tone applied, we then identify the circuit we are working on using a probe that gives an audible identification by getting louder the nearer the pair you are trying to isolate. Probes are more commonly referred to as 'Swaffers' or 'Wands' .... depending on which part of the country you are working in. :)