My golden retriever thought it would be fun to pull on the telephone wire on the outside of the house. The consequence being that she pulled the wire out of the master socket. There appears to be 4 wires - orange, black, green, and white. There are 3 screw-down terminals labelled A, B, and E. Can anyone tell me which wire goes to which terminal?
Telephone master socket wiring
- Thread starter stevie-c
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A B are the line, ignore E
Gr and BL to B and A
OR
Or and Wh to B and A
Depends which pair BT used.
Gr and BL to B and A
OR
Or and Wh to B and A
Depends which pair BT used.
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Bear in mind if you have broadband, with some, polarity is important.
I found that out when doing telephone work recently.
If you reverse polarity, broadband does not recognise the fact that a line is present. Furthermore, you cannot dial out. Well, you CAN, but the number is not recognised.
I have a plug in tester which tells you the polarity of AB and whether you have term 3 connected.
It was made by AX, but they no longer make them, so try Googling plug-in telephone wiring tester.....
I found that out when doing telephone work recently.
If you reverse polarity, broadband does not recognise the fact that a line is present. Furthermore, you cannot dial out. Well, you CAN, but the number is not recognised.
I have a plug in tester which tells you the polarity of AB and whether you have term 3 connected.
It was made by AX, but they no longer make them, so try Googling plug-in telephone wiring tester.....
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Paul_C
Assuming only a single line to the house, it will likely be on the orange/white pair. The green/black would normally only be used in such a case if the first pair had developed a fault and the line had been swapped to the second pair.
The standard for this new cabling is white for ring (B) and orange for tip (A). That is completely contrary to the long established convention of white being in the tip group of colors and orange in the ring group, but then BT has not always been logical!
P.S. If the line does happen to be on the second pair, then the standard coding is green=A, black=B.
The standard for this new cabling is white for ring (B) and orange for tip (A). That is completely contrary to the long established convention of white being in the tip group of colors and orange in the ring group, but then BT has not always been logical!
P.S. If the line does happen to be on the second pair, then the standard coding is green=A, black=B.
swapping the A and B connections won't effect a normal phone but some modems have been known to be fussy
you should be able to test with a multimeter set on DC voltage but im not sure which way round is normal off the top of my head
you should be able to test with a multimeter set on DC voltage but im not sure which way round is normal off the top of my head
In our area, Orange and White are generally the first line, Green and Black either spare or a second line.
Polarity is not normally important (hadn't heard that it made a difference to caller ID, I will experiment).
Orange and Green is usually B. Although when DP's are wired, very often the pairs become reversed.
Polarity is not normally important (hadn't heard that it made a difference to caller ID, I will experiment).
Orange and Green is usually B. Although when DP's are wired, very often the pairs become reversed.
P
Paul_C
Tip/A = Positive, Ring/B = Negative.plugwash said:
As telephone supplies have the positive side grounded, on an idle line you should read about -50V to ground on the B wire, zero on A.
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plugwash said:
Lectrician said:
As already described, my customer could not access internet with his broadband modem (some are polarity sensitive), and furthermore, the phone would not dial out. It would physically dial the number, but would without fail announce the number as "not recognised".
When I reversed polarity, everything worked as it should.
Maybe due to a fault on the ringer cct - this is polarity dependant.
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Don't think so, I have fully tested the system and it is aOK....
Even BT were baffled!
Even BT were baffled!
P
Paul_C
I assume you could hear DTMF being sent as you pressed the buttons? Did the first digit dialed break the dialtone?securespark said:
At what point did you cut over to the "Not recognized" recording? Was it on the initial digit, or were you able to dial the full number before getting it? Or did it just timeout to the recording?
If the phone was actually sending DTMF tones, then the only thing I can think of is that the tone generator was either sending off-frequency or at a reduced amplitude when the polarity was reversed.
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Indeed. It would dial the number normally, but instead of a ringing tone, you would get the message.
Yes, you could hear the DTMF, and the first digit broke the dial tone.
As I say, even BT engineers were baffled...
But that does not mean too much. I mean, I'm not being rude, but if you go to one GP, s/he may not be aware of a particular health problem whereas others may. Same with engineers, too.
Yes, you could hear the DTMF, and the first digit broke the dial tone.
As I say, even BT engineers were baffled...
But that does not mean too much. I mean, I'm not being rude, but if you go to one GP, s/he may not be aware of a particular health problem whereas others may. Same with engineers, too.
P
Paul_C
Well, I used to be one of those BT engineers, and I can't say I've ever come across this problem before.
Some of the early TouchTone phones were fussy about polarity, but a reversal would just prevent the tone generator from working at all. In fact with the exchange equipment in use at that time it was quite normal for the line polarity to reverse upon supervision, so you could dial normally but the DTMF pad would become inoperative once the called party answered.
Off-frequency tones with reversed polarity is the only possibility I can see which makes any sense. The only way I can see for that to happen is if part of the bridge rectifier feeding line power to the DTMF generator was faulty. It's certainly a strange fault, whatever the cause.
Some of the early TouchTone phones were fussy about polarity, but a reversal would just prevent the tone generator from working at all. In fact with the exchange equipment in use at that time it was quite normal for the line polarity to reverse upon supervision, so you could dial normally but the DTMF pad would become inoperative once the called party answered.
Off-frequency tones with reversed polarity is the only possibility I can see which makes any sense. The only way I can see for that to happen is if part of the bridge rectifier feeding line power to the DTMF generator was faulty. It's certainly a strange fault, whatever the cause.
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