live line

[steptoe]

got a job ripping out a load of telephone/network cable.

about 2 mile!!! (in a warehouse)

what is the easiest/simplest way of determining a live/working cable?

a lot of this cabling will be left in situ as it is still active, is there a quick and easy way to tell a live/online cable and a redundant one?

thanks

Albert.

 

[Mr Sworld]

Telecom engineers use a transmitter that gets plugged into the cable at the termination end and a hand-held receiver that will pick up the signal and beep. A bit like the fuse-finders that Robin, et al, sell.

In fact, just like this:

Telecom tracer

 

[steptoe]

I have one Mr S,

unfortunately I need to know the dead cable before I disconnect it.

is there still a DC voltage present on a telecom cable? or is that now only present on a ring tone?

 

[steptoe]

Telecom engineers use a transmitter that gets plugged into the cable at the termination end and a hand-held receiver that will pick up the signal and beep. A bit like the fuse-finders that Robin, et al, sell.In fact, just like this:

Telecom tracer

apologise Mr S,

looks like mine, smells like mine, even costs less than mine!!!!

but does more than mine.

seems to work on live/dead lines this one,

I'll give it a try, cant be a bad gamble for the price. mine cost a small fortune more and dont do live test.

Thanks,

 

[Mr Sworld]

Are all these cables coming back to Krone connector blocks at some point at the internal exchange (if they have one)?

 

[SPECIAL LOCATION]

I have one Mr S,unfortunately I need to know the dead cable before I disconnect it.

is there still a DC voltage present on a telecom cable? or is that now only present on a ring tone?

Yes there is a voltage..

you will get 50v dc or thereabouts on a live telephone line..

or to be more precise 0 and -50v!!

stricly speaking telephone lines do have a polarity.

an engineers test handset normally has a polarity button which lights up red or geen if correct or incorrect...

this just detects the 50v dc!

Most modern telephone equipment is not polarity conscious..

SL

way back yonder did an apprentiship in telecommunications?

I can still remember that bit......

and I've still got my test handset..

good when doing phone sockets at customers houses

 

[steptoe]

multiple and i mean multiple BT connection boxes, 18"X10" approx,

when I said about 2 miles of cable I really wasnt just saying that.!

an old warehouse with loadsa upgrades without old stuff being removed

 

[steptoe]

Yes there is a voltage..you will get 50v dc or thereabouts on a live telephone line..

stricly speaking telephone lines do have a polarity.

an engineers test handset normally has a polarity button which lights up red or geen if correct or incorrect...

this just detects the 50v dc!

Most modern telephone equipment is not polarity conscious..

SL

way back yonder did an apprentiship in telecommunications?

I can still remember that bit......

and I've still got my test handset..

good when doing phone sockets at customers houses

I only need to determine active or redundant line.

all redundant lines to be removed.!

 

[SPECIAL LOCATION]

I only need to determine active or redundant line.all redundant lines to be removed.!

Trouble is with most modern digiatal exchange equipment..

the features of a phone could be bared or enabled by software..

i.e. the line could still be live.

but barred from dialing any numbers!!!!

thats what BT often do when you move house..

e.g.

you can plug in a phone hear dial tone (the 50v supply you would see with your meter)

but when you try to dial

the nice voice says

"this number is not recognised"

so the line is "LIVE" but dead in so much as you cant dial out!!???

you would need to know if they have actually physically diss' the lines the the warehouse PABX internal excahange equpipment..

or just software barred them???

This dont really make it easier for you though

SL

 

[Mr Sworld]

We actually have BT engineers permanently on-site at work (weird I know!) so I shall ask them tomorrow. It might be just sticking a multimeter across the pairs at the boxes and seeing if there is 50V present as SL suggests.

I shall follow this up in the morning.

 

[Mr Sworld]

Ok, just read SL's new reply. Ain't going to be as easy as a multimeter test! :_|

 

[Mr Sworld]

apologise Mr S, looks like mine, smells like mine, even costs less than mine!!!!

but does more than mine.

seems to work on live/dead lines this one,

I'll give it a try, cant be a bad gamble for the price. mine cost a small fortune more and dont do live test.

Thanks,

Sorry Steptoe. Don't buy this item! I've just found out it's a Chinese company that sells them so they will probably be a pile of poo!

 

[steptoe]

Trouble is with most modern digiatal exchange equipment..the features of a phone could be bared or enabled by software..

i.e. the line could still be live.

but barred from dialing any numbers!!!!

thats what BT often do when you move house..

e.g.

you can plug in a phone hear dial tone (the 50v supply you would see with your meter)

but when you try to dial

the nice voice says

"this number is not recognised"

so the line is "LIVE" but dead in so much as you cant dial out!!???

you would need to know if they have actually physically diss' the lines the the warehouse PABX internal excahange equpipment..

or just software barred them???

This dont really make it easier for you though

SL

thanks for all your help guys, I think the site owners are just wanting all "actually not connected" cables removed.

I can prove this with a 50v (or lack of) test? yes?

there has been loads and loads of additions/replacement cables put in over time but the old cables have just been cut at various junction boxes etc and left in situ.

I will explain to them that I will only be removing the cables that are electrically dead.

the live line but not working bit may get a bit more time consuming tracing each cable at the moment.

Im pretty sure that will be what they are wanting.

it may grow to be all excess cables in time but for now I think just a good tidy up/housekeeping routine.

its all down to a time scale cos its a 24/7 operation and certain areas I only have access to for a 2hour window on a tuesday!! (H&S meeting or something I think)

 

[Mr Sworld]

Right, talked to my good BT buddies today.

The gist of it is to 'listen' to the pairs at the incoming boxes. If you have a butt test phone then attach the croc-clips to the individual pairs (if not get a old handset from a normal phone and put croc-clips on the wires from the ear-piece), if you have a dial tone, it's still live. However, if the service has been 'unbundled' at the exchange you will not hear a dial tone.

If you don't hear a dial tone test the pairs with a multi-meter, a live line will have 50V dc on it, a ISDN line will have 90V dc however.

So if you don't get a dial tone or a voltage it's probably dead. Even the BT engineers cannot tell a software diss'ed line however from a terminal block.

However on a positive note, due to me asking the BT guys about this they gave me a 'butt test phone' they happened to have lying around, because of my interest in the subject!

 

[SPECIAL LOCATION]

However on a positive note, due to me asking the BT guys about this they gave me a 'butt test phone' they happened to have lying around, because of my interest in the subject!

Good one M8! :^O and its not even christmas!B)

I still have my old Test butt from donkeys years back..

they are probably better now..

but it still does the biz when doin phone sockets for customers!!!

You better go and sub-contract yourself ouf for stepoe:^O:^O:^O

 

[Mr Sworld]

How old a 'butt'? Does it have batteries in it or the little hand crank on the the side to deliver the test voltage?

Had a weird 'telecoms' day today actually. The ADSL lines went down today at 9am, spent the rest of the day checking cat5 lines and trying to re-configure windows to see the local area network from the routers. Then at 3pm it all re-appeared and worked perfectly! :_|

No idea what happened and pretty sure it wasn't anything to do with what I did. However I did 'quietly' take the praise from the 'hotties' in the admin office! ]

 

[steptoe]

How old a 'butt'? Does it have batteries in it or the little hand crank on the the side to deliver the test voltage?Had a weird 'telecoms' day today actually. The ADSL lines went down today at 9am, spent the rest of the day checking cat5 lines and trying to re-configure windows to see the local area network from the routers. Then at 3pm it all re-appeared and worked perfectly! :_|

No idea what happened and pretty sure it wasn't anything to do with what I did. However I did 'quietly' take the praise from the 'hotties' in the admin office! ]

surely that was down to me removing the old redundant lines and giving the hotties more bandwidth,

tell them to show me the appreciation a bit more!! B)

thanks for the info, sounds good to me, I think I should be able to get a good enough start (to keep customer sweet) with what I now know.

thanks again.

(ps, is it possible to actually obtain a proper butt phone?, normally)

 

[Mr Sworld]

Evening Steptoe, you can find butt phones on e-bay usually.

 

[steptoe]

http://cgi.ebay.co.uk/Harris-TS30-Data-Safe-Telephone-Butt-Set_W0QQitemZ260224052174QQihZ016QQcategoryZ40004QQrdZ1QQssPageNameZWD1VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247

is this the thing? ?:|

 

[Mr Sworld]

It is but it's an old one. And at