Missing cable

[Dark Fiber]

I've just been cold-called, for the umpteenth time, to try to get me to add TV to my BB&phone package. I explained (for the umpteenth time) that I didn't want it, not least because I am worried that splitting the signal will degrade my BB service. Today's man said this was not a problem and stated explicitly what the others have only hinted, that "there are three cables coming into your house, one for TV, one for broadband and one for telephone".
How many of us are missing a cable and what should we do about it? ;)

[Turkey Machine]

I've just been cold-called, for the umpteenth time, to try to get me to add TV to my BB&phone package. I explained (for the umpteenth time) that I didn't want it, not least because I am worried that splitting the signal will degrade my BB service. Today's man said this was not a problem and stated explicitly what the others have only hinted, that "there are three cables coming into your house, one for TV, one for broadband and one for telephone".
How many of us are missing a cable and what should we do about it? ;)

He's buls**ting you quite badly. There's only one cable going to the box on the wall, from there it's split. :) To be quite honest, it's unlikely to degrade the signal unless you're doing long cable runs. The telephone one is a separate one though, I believe, though I don't have one so can't comment fully on it. ;)

[MovedGoalPosts]

There are two cables to a property, the phone line which is moulded into the plastic sheathing of the coaxial type cable. The coaxial does both TV and broadband.

In most cases the street feed will support cable and TV without any issues. I actually have 20meg broadband a V+ and V box without any problems.

[Chris]

He's buls**ting you quite badly. There's only one cable going to the box on the wall, from there it's split. :) To be quite honest, it's unlikely to degrade the signal unless you're doing long cable runs. The telephone one is a separate one though, I believe, though I don't have one so can't comment fully on it. ;)

Technically he's not bul-etc-ing ... all the cables for the different services are split out at the wall box, so as far as the customer is concerned there really are three separate cables coming 'in' to the house. It sounds like a reasonable, non-technical explanation for the benefit of any ordinary customer who does not normally supplement his understanding of cable issues by visiting forums like this one.

We used to have two cables coming into the lounge (1 for TV and 1 for phone) and a third running up the external wall and into the spare bedroom for BB.

Splitting the cable is not a problem provided it's done by a competent VM installer who has the know-how and the kit required to ensure the overall signal level in your home is sufficient for the services you have ordered.

[popper]

actually chris, rob is right , there are two and only two sets of cables..

the twisted pair (8 core wire twisted together, were you could make it into cat5 ethernet as its the same grade as cat5, around here at least, although they may have used a cheaper grade/lesser stranded twisted pair in other area's though?) phone line.

and the digital TV AND the broadband signals are send down the other 75 Ohm single core braided one, virtually split into different frequences....

[Chris]

actually cris rob is right , there are two and only two sets of cables..

I know, I'm simply highlighting the difference between the technically correct explanation, and the apparently correct, simplified explanation for the non-technical.

Whatever comes up your garden from the street cab - as you say, two cables, but sheathed as one - it is split at the wall box at the house. So for the purposes of explaining to a customer, I think it's unfair to accuse the salesperson who gave the explanation to the OP as 'bull****ing".

[Stephen]

I've just been cold-called, for the umpteenth time, to try to get me to add TV to my BB&phone package. I explained (for the umpteenth time) that I didn't want it, not least because I am worried that splitting the signal will degrade my BB service. Today's man said this was not a problem and stated explicitly what the others have only hinted, that "there are three cables coming into your house, one for TV, one for broadband and one for telephone".
How many of us are missing a cable and what should we do about it? ;)
Adding the TV service will not affect your BB in any way at all. They do use the same cable but are on totally different frequencies so will not interfere with each other.

[beeman]

...(8 core wire twisted together, were you could make it into cat5 ethernet as its the same grade as cat5, around here at least, although they may have used a cheaper grade/lesser stranded twisted pair in other area's though?) phone line.

6 core in the old cambridge cable franchise :)

[popper]

well, you only need 2 wires for the master phoneline bit, so VM could use the spare unused 4 wires for managed ethernet from your street CAB if its within 300 feet, even in cambridge too ;) ,but thats slightly OT for this missing cable thread...

[Dark Fiber]

Adding the TV service will not affect your BB in any way at all. They do use the same cable but are on totally different frequencies so will not interfere with each other.
AIUI the splitting is entirely passive and independent of frequency- at best, only one half of the signal presently arriving will go to my modem. (I have reason to believe that I am already on the highest power "tap" available.)

BTW there is no doubt in my mind that the salesman wanted me to believe that BB and TV are entirely separate coax cables.

EDIT: see below for the arrangement I would expect to have foisted on me.

[Darrenp]

Technically he's not bul-etc-ing ... all the cables for the different services are split out at the wall box, so as far as the customer is concerned there really are three separate cables coming 'in' to the house.

Not in my house it aint, there's always just been the 1 cable outlet and 1 phone outlet. (and a fm radio output if I remember correctly!)

My cable outlet then has a very short patch lead from that 1 outlet into a splitter which just lays on the carpet next to the wall outlet.

Anyway, back to the issue, splitting the cable shouldn't have any effect on the BB performance, my BB cable runs from downstairs splitter to upstairs and is atleast 25 ft and my BB has always ran at it's correct speed very reliably.

[Chris]

Not in my house it aint, there's always just been the 1 cable outlet and 1 phone outlet. (and a fm radio output if I remember correctly!)

My cable outlet then has a very short patch lead from that 1 outlet into a splitter which just lays on the carpet next to the wall outlet.


Maybe that works in a small flat, but in a three-bedroom house it's nice to have the wall boxes in the different rooms where you want them. ;) :D

[Darrenp]

Maybe that works in a small flat, but in a three-bedroom house it's nice to have the wall boxes in the different rooms where you want them. ;) :D

Na, thats just too posh. :D

Slinging the cable out the downstairs window in in through the upstairs 1 is definately the way to go. :D:D:D

[piggy]

actually chris, rob is right , there are two and only two sets of cables..

the twisted pair (8 core wire twisted together, were you could make it into cat5 ethernet as its the same grade as cat5, around here at least, although they may have used a cheaper grade/lesser stranded twisted pair in other area's though?) phone line.

and the digital TV AND the broadband signals are send down the other 75 Ohm single core braided one, virtually split into different frequences....

two pairs in all ex cwc franchise

[thamesvalley]

If you're already on the top tap and are borderline for signal strength, then chances are that splitting the cable again may have a detrimental affect on your services.
In my experience, this tends to affect television services more than broadband though. (unless it is the return path signal that is borderline and then it would affect both)

However... there is a wonderful device called an HDU (home distribution Unit) that is basically a powered splitter which results in turning 1 input into 4 outputs without affecting the signal strength. This device saves the need for upgrading your drop cable or pulling in an additional one.

If you go for the installtion and your signal levels are too low then virgin installer or service tech will/should make arrangements to provide an alternative solution to boosing the signal which will be either an HDU, RG11 upgrade or additional drop cable.

[Dark Fiber]

However... there is a wonderful device called an HDU (home distribution Unit) that is basically a powered splitter which results in turning 1 input into 4 outputs without affecting the signal strength. This device saves the need for upgrading your drop cable or pulling in an additional one.


Many thanks for this information- I was not aware of that option.

[Jonnymeg]

Many thanks for this information- I was not aware of that option.

You really shouldn't worry about it mate, you are being overly cautious.
It is highly unlikely that installing TV will give you any problems whatsoever as that is how the system is supposed to work.
The feed to your street is already split 25+times in the green box down the road, thats all that's in there, one big splitter! It is also possible that your individual feed from that tap plate is split again if it is a busy area.
The whole network is ram packed full of splitters and adding a 2 way at your house will only loose you 3.5db and probably not noticable.

What you should do is go to http://192.168.100.1 and login with the name ROOT and password ROOT.
Look for the downstream power level and it should be between +10 and -10.
You can get away with power outside this range but it is not reccomemded.
Take your level and subtract 3.5. If it is still between +10 and -10 you will be fine.

[Dark Fiber]

..., you are being overly cautious.
It is highly unlikely that installing TV will give you any problems whatsoever
What you should do is go to http://192.168.100.1
Look for the downstream power level and it should be between +10 and -10.
You can get away with power outside this range but it is not reccomemded.
Take your level and subtract 3.5. If it is still between +10 and -10 you will be fine.
Alas, I have a TJ210. If I could see my power levels, I might be less cautious! :)

[Jonnymeg]

Alas, I have a TJ210. If I could see my power levels, I might be less cautious! :)

There are other ways to query the data.

http://homepage.ntlworld.com/robin.d.h.walker/docsdiag/

[Dark Fiber]

There are other ways to query the data.

http://homepage.ntlworld.com/robin.d.h.walker/docsdiag/

AIUI this avenue was blocked some time ago for "network security" reasons. :(

[SnoopZ]

Alas, I have a TJ210. If I could see my power levels, I might be less cautious! :)

You really should get that modem changed, although it'll probably cost you.