Is it correct that the BT drop wire only has 2 wires connected in the junction box? Yet the output side of the junction box that goes to the actual telephone sockets has 4 wires. So in effect 2 of these wires weren't doing something or were they?
When I cut my external cable by accident, I had to connect all 4 wires to get my broadband working correctly it wouldn't work with 2. Which I can't fathom out. However since I had to renew the cabling from the junction box in the loft, I have only connected 2 wires and the broadband appears to be fine.
Here is a link to the junction box as a picture is worth a 1000 words.
formatting link
I'm asking is should I just leave as it is as 2 wires or go back to the
4?
Just 2. Perhaps your external cable had been connected with two sets of paired wires to try and get a better signal or perhaps as part of a fault repair when the existing pair of wires went bad the engineer just added a second pair of wires without removing the duff pair although I can't see why. Every external line to the nearest telephone pole has spare wires in the cable. I'm sure if you'd worked out which 2 of the 4 wires was the good pair it would have worked ok.
The second pair is for a second line. If you don't have the second line, you don't need to worry about the second pair.
I do have a comment regarding your junction box though - your cables on the right are 4 pair UTP (unshielded twisted pair) which means that they'll have best performance if you use wires as they are paired. In other words, if you only need to use one pair, you need to use blue and white-blue conductors out of that 8-conductor cable. You could have used other pairs, too, but blue is traditionally the pair #1 and it's also one of the shortest conductors (because of its twist).
You've used one conductor from each pair (only blue but not white-blue) which left the other conductor in the pair unconnected and thus the pair imbalanced, collecting EMI. It's also not recommended to connect the two conductors of the pair together to double up the cross-section (and use another shortened pair as the second conductor) as it appears has been done to the orange pair. In this case there is very little twist between pairs in the cable and therefore it's no longer unshielded *Twisted* pair. That, again, makes it susceptible to EMI.
Cheers!
------------------------------------- /\_/\ ((@v@)) NIGHT ():::() OWL VV-VV
> Here is a link to the junction box as a picture is worth a 1000 words.
I did have a second line (now no more) but this was connected via the black and green on the drop wire. It didn't actually come in to the junction box! The second pair you refer to go to the actual sockets and are connected there, hence 4 wires in the sockets yet only 2 in the junction box.
Thanks for that tip. I never installed the wiring that is how I found it. (I took this picture before I changed the untwisted wiring)
Again thanks. I'll make sure I use a pair. However I notice the drop wire is untwisted so would using twisted for part of the journey, really not have any benefit?
Cheers. The orange/white cable isn't actually connected. I think looking at the picture it is just a stray cable.
The external line has only two wires. The master socket splits off a third, and in some cases a fourth, so the internal line has (up to) four wires - not all of which are necessarily needed.
The pair that connect direct to the external line are usually blue and white-blue. These carry voice, ringing, and ADSL. An ADSL router connects direct to this pair (if you use a filter, the ADSL port is a pass-through). Phones connect to this pair via a filter, or direct if ADSL is not in use.
The orange wire is the bell wire, which carries only ringing. Most phones don't need this and get their ring signal from the blue pair - unless you have phones with actual bells in. Leaving this unconnected can improve ADSL - the blue wires are a twisted pair but adding an extra untwisted wire introduces noise.
The white-orange wire is earth. Nothing uses this nowadays on a standard phone line, so this is not connected.
The green wires, if present, are not used.
There's something rather odd about your photo. The black cable is presumably the incoming BT cable. Two pairs are connected, so presumably two lines. One is crimped to the blue wires leading off the bottom of the photo, so presumably that leads to a BT master socket. The other pair goes into the junction box, where it all gets a bit confused. This is BT's side of the master socket, so there should only be one cable - but there are two, and the top one looks like cat5 rather than phone cable (it is marked 4pr, phone cable has only three pairs). Also the bottom terminal has three wires attached. There should only be one cable on the right-hand side. The blue wire should be attached to the top terminal, the white-blue to the bottom terminal, and nothing to the middle one. The orange and green wires should not be connected to anything. This should run to a BT master socket. Any extensions should run from there - either from the removable front if it's a linebox, or via a plug if it isn't. It looks like someone has run an extension on the cheap by tapping into the junction box. If BT find out this has been done then they can refuse to fix any faults until they've corrected it - which they charge quite a lot for. Also as the line isn't on a proper pair, it won't do ADSL speed any good.
Thanks for that. Some very good information there.
This was a second line that had a completely different cable connected to it. I used to use this as an always on dial-up so our main line wasn't always engaged. It has since been disconnected so those wires can be ignored.
That is just a loose wire (orange /white) that isn't connected.
The top wire (4pr) runs from one side of the loft to the other and into another junction box. From there the wire changes to proper telephone cable wire and runs into my bedroom. Which I thought was the BT master socket but since part of the run is in 4pr wire I doubt very much now that it is. The bottom wire ran all the way down to the dining room and terminated in what looked like a small accessory socket!
I think you are right. Although I haven't done any work to the telephone system apart from yesterday when I changed the wire going to the dining room.
Pole to house - two wires is normal as a figure of 8 copper covered steel core (grey). Later type is black, 2 copper cores, with two steel reinforcing wires to form a round outer.
On an older installed, those two incoming wires may have been jointed in a joint box to run to a new phone location using 2x pair or 3x pair. With the spare wires used to double up or simply left unused.
The above should go to a master socket and from the master two pairs (4 wires) needed for most phones to work correctly in extra sockets. Broadband can manage across just the two main wires from the pole.
No the wire at the junction of the C & R is the "anti-tinkle" as well as the "bell" wire. It is shorted to the "A" wire (pins 3 & 5) when the dial is moved off the backstop.
The other one would be earth for earth recall. Very rarely used these days.
OK, one of those should be the master ond one a secondary. Does either of them have a BT logo on it? If so, that's almost certainly the master. If you can take the front off the socket, the master will have a capacitor, resistor and surge supressor on the back.
If you want to make it look "normal", then you need the wire to go from the junction box to the master socket, which must have a BT logo, using standard phone cable. There should be no branches before the master socket. Since it sounds like neither socket is a linebox (with a split across the middle), then the extension to the other room should be plugged into the front of the master socket.
From your picture, the line is on the orange and blue wires, which aren't a pair. Each wire is twisted with its corresponding white: blue with white-blue, orange with white-orange, green with white-green. The twisting reduces interference that can slow down ADSL connections - two wires from different pairs aren't twisted with each other, removing this advantage.
Thanks Mike. Your explanation of the wires being twisted with its corresponding white wire makes sense to use as a pair however this drop wire doesn't have the corresponding white wires, just solid coloured wires and from what I can see they aren't twisted pairs.
corresponding white wire makes sense to use as a pair however
wires and from what I can see they aren't twisted
The white/orange and green/black wires are mutually twisted into pairs. the pairs themselves are also mutually twisted at a lesser pitch.
The twist in telephone wire is not as pronounced as CAT5 but is very important nonetheless to avoid crosstalk of speech frequencies and to act as a reasonably efficient transmission line for radio frequencies (ADSL).
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