Help needed re-wiring a BT junction box

[Ratbiter]

I'm replacing a BT78b socket, I have a "Can do" attitude that often becomes a "Oh no you can't", so hopefully with your help it can be a "can do" result as I ned the line up and running again ASAP

Hopefully I'm giving you all the info you need to assist me.

The socket is a BT78b image can be found here (http://www.telephonesuk.co.uk/images/small/78A_small1.jpg)


and coming into the back of it from outside comes the cable and orange/green/black/white wire enter this box. (which are now not connected to anything, previously two went to the connections in the box Top row(white=2 and orange=5 I think) and two went to a jellybean connector each with the connection being made with two of the wires from one of the extentions, and the other line went to bottom row Blue=2 and orange =5 again I think)

Now there was/is two seperate phone lines (different numbers contracts) extentions connected to this box both have 4 wires which are the same Brown/green/orange/blue.

What I need to know is where all these wires goto which ones go to which terminals/sockets on the box and wich ones goto the Jellybean connections, and hopefully I'll have two phonelines again by the end of the day.

 

[bernardgreen]

The drop wire colours are

The BT Drop Cable (The cable coming from the outside world)

This often has Orange, White, Green and Black wires. Usually (but not always) Orange and White are the active pair and go to connections 2 and 5. In some master boxes (such as the type with a removable front section) they go to two connectors marked A and B.

Which way around they are connected usually doesn't matter but as Rick Hughes kindly pointed out some modems (especially older USA sourced ones) and some answering machines are fussy about polarity, so it's wise if possible to check the voltage on the line and connect -48V to the B leg (J2) and 0V to the A leg (J5).

If you have underground wiring with a small grey connection box by the door the internal cabling will usually be the same type and colour as the extension cabling.

So one line is on the Orange and White. the other line is on the Green and Black.

The jelly beans may still have a bit of the drop wire still inside them. if they do then that will tell you which of the drop cable wires go to the other wires in the jelly beans

The questions are

[1] why did someone disconnect the box
[2] why did that person not make a note of which wires went where.

 

[Ratbiter]

No wire in the jellybean Threw them away before I understood what they were etc.

I disconnected then because one line was no longer needed and the socket for the 2nd line was in a better place so swapped wires over just using a little tape as a temp measure, and never got around to making it a premament job, as it was hid behind a sideboard so didn't get distrubed etc. However moved furniture and Cats discovered the wires.
Had originally jotted notes down on a scarp bit of paper but that was many months ago and has disappeared to where all notes disappear too.

So still need feed back on the above please.

 

[bernardgreen]

Unless you want to confess and call in BT / Openreach to repair the situation you will to try a few combinations.

Did you have a working phone line before you disconnected the junction box ?

Do you have a multi-meter that can measure volts ( 50 volts DC ) and ohms. ( resistance ) ?

Do you have a plug in phone that works. ( Not a cordless one ) ?

 

[Ratbiter]

Can't really afford the £129

Yes

No

Yes

 

[bernardgreen]

First thing is to identify which twisted pair of be/wt and wt/be wires go to the socket you want to use for the phone.

( be/wt = blue with white and wt/be = white with blue )

Plug the phone in and leave of hook. If you had a multi-meter you would simple test each of the blue/white pairs till you found one with a resistance. Without a meter you can only tap the wires onto a 1.5 volt battery ( or a 9 volt one ) and if you have the correct pair then there will be a click in the earpiece of the phone each time you connect and dis connect the battery.

When you find the blue/white pair that connects to the phone you need to connect that pair to the incoming pair, try the Orange and Black wires first. If you are lucky and the phone line is still active you will get dial tone in the phone. If not try the other incoming pair. It won't matter which way round you c0nnect them.

That junction box is almost certainly connected via the blue/white pair(s) to a master socket(s) somewhere. As the master socket has been disconnected from the incomer it is not impossible that a routine line test ( automatic system ) has detected that disconnection and if the disconnect has lasted few days then the line may be parked and thus "out of service".

If you get dial tone then call a mobile or other phone with caller display to find if the number is the one you had before or is the number of the other line coming to the house.

Did you have two lines before ? If you only ever had one line to your property it is possible ( but luckily highly unlikely ) that the other incoming pair goes to someone else's phone. ( sometime happens when a house is converted to flats and the phone wiring has been bodged by the builder )

 

[kbdiy]

Ok the most likely combination is:
incoming external - orange/white
internal - blue/orange
Connect incoming orange to internal orange, incoming white to blue.
Internal cable blue to 2 of line jack, orange to 5.

If no dial tone try the green/black incoming, polarity is not critical.

 

[Ratbiter]

Yes there was two lines coming to the house, Mine and the daughters.

 

[steve1976]

The drop wire colours are

The BT Drop Cable (The cable coming from the outside world)

This often has Orange, White, Green and Black wires. Usually (but not always) Orange and White are the active pair and go to connections 2 and 5. In some master boxes (such as the type with a removable front section) they go to two connectors marked A and B.

Which way around they are connected usually doesn't matter but as Rick Hughes kindly pointed out some modems (especially older USA sourced ones) and some answering machines are fussy about polarity, so it's wise if possible to check the voltage on the line and connect -48V to the B leg (J2) and 0V to the A leg (J5).

If you have underground wiring with a small grey connection box by the door the internal cabling will usually be the same type and colour as the extension cabling.

So one line is on the Orange and White. the other line is on the Green and Black.

The jelly beans may still have a bit of the drop wire still inside them. if they do then that will tell you which of the drop cable wires go to the other wires in the jelly beans

The questions are

[1] why did someone disconnect the box
[2] why did that person not make a note of which wires went where.

if you connect orange and white from outside to 2 & 5 in the socket you should get dial tone. dial 17070 and it will tell you the number you are on.also connect internal to orange and blue

 

[bernardgreen]

Connect incoming orange to internal orange, incoming white to blue.
Internal cable blue to 2 of line jack, orange to 5.

NO . that would not be a twisted pair and hence noise levels could be much higher.

 

[trowelhead]

Connect incoming orange to internal orange, incoming white to blue.
Internal cable blue to 2 of line jack, orange to 5.

NO . that would not be a twisted pair and hence noise levels could be much higher.

YES. If the internal cable is the 'new' 2502 type that Openreach use.
Pair 1 blue and orange
Pair 2 green and brown

 

[Ratbiter]

here's an update but first in rply to above post. Both internal lines end with an extention box which has openreach on them, Line 1 The original installed one has just a socket to plug the phone in. this is the discontinued line. Line two has two sockets one for the phone and another for the Modem.

Progress or not? after sitting on floor for 2 hours and getting a deadleg I've made little progress but still no proper connection.

First I went to the socket I want to get working (which is the 2nd line installed by BT if that makes a difference) took the cover of the socket and found it has the orange a blue wires connected.

went back to the drop socket (the one where the wires come into the house) and put the incoming white wire into slot 2 and the orange into slot 5 (this is how BT had the wires with the 1st line installation with the 1st line blue wire going to slot 2 at he bottom and the orange one going to slot 5 at the bottom) so I copied that set up and the 2nd line became line 1 which is now disconnected the service is no longer live on this line. the 2nd line seemed only to be connected via the jelly beans, which I do not have now i.e black and green incoming wire went to jelly bean to link with Blue and orange wires on the 2nd line)

So I swapped the incoming black and green wires for the Orange and white ones thinking these must be the wires used for the 2nd line, but no I got no dial tone or anything, switched the black and green but still nothing.

so I put all 4 incoming wire in up top and fitted one (blue)wire into slot 2 at the bottom then just touched the the slots below the above connected wires and the foloowing happend I 1471 it when I got a dial tone and got two message at the same time one saying when I got the last call and the other saying number dialed not regonised.

:j:T:j:T:j I was thinking I'm winning but no I continued the above process and found I only got a dial tone when one of the two bottom wires was connected the the White wire, Nothing happends at all when the black wire is connected to either of the bottom 2 wires and I get the 2 messages when I connect to the green wire above and the old line if I connect to the orange one. It doesn't seem to matter which slot at the top I'm in white always gives a dialtone, black seems dead and orange or blue connects to either the old line or to both lines.

Time for a cup of tea, then back to it, but can't see what other configurations I can do (fingers crossed one of you will have the answer for me)

 

[cajar]

if you get 2 messages read back at the same time it means a) you have two live lines at the bt78 and b) you have somehow put them in contact with each other.

a picture of what you have done would help.

edit I just read that one message is number not recognised. this is a stopped line, find out which pair it is and remove it altogether. it'll either be on the orange white or green black.

 

[Ratbiter]

edit I just read that one message is number not recognised. this is a stopped line, find out which pair it is and remove it altogether. it'll either be on the orange white or green black.

Pretty sure the 1st installed line (now discontinued) is white and orange as you suggest. But when I remove the white one I do not get a dialtone at all. neither the black or the Green seem to provide power? like the white one does.

Picture won't help much as I've tried just about all combinations except using slots 1 and 8 as I've read elsewhere they are often not used at all. But may have to try them too

 

[Ratbiter]

just a thought but will I need to connect the discontinued line to make the 2nd line connect. as I've removed the wires from the first line completely