Cat6/Telephone  - Page 1
Forum section: electronics / beginners

author: Invader75
author_rank: Newbie
timestamp: February 02, 2019, 02:04:46 pm
content: Hi,We've just had an annexe built. I supplied the Cat6 cable for the electrician to connect up. Just been down there and it appears he's connected it up as a phone line. 🤔Couple of questions. Obviously I can change the connector and socket over easy enough. But, as we don't yet have a phone line down there yet, is there anyway to use the Cat 6 to carry both a phone signal and internet. I know this sounds like a stupid question, and it probably is. ;-)

author: Ian.M
author_rank: Super Contributor
timestamp: February 02, 2019, 02:27:17 pm
content: Although slower ethernet modes only need two pairs, its a *really* bad idea to mix ethernet and telephone in the same cable as it drastically increases the risk that you'll fry everything on your network if there is a lightning strike near your house or the phone line to it.

author: Invader75
author_rank: Newbie
timestamp: February 02, 2019, 03:05:06 pm
content: Ok. Fair point. I must add we're in the suburbs of Cardiff, Wales, with the annexe being single story timber frame.

author: FrankE
author_rank: Regular Contributor
timestamp: February 02, 2019, 07:24:43 pm
content: Don't mix them in the same cable. There's 48V on a telephone cable. The ring signal is 50V ac. There is a risk of crosstalk.

author: Invader75
author_rank: Newbie
timestamp: February 02, 2019, 08:03:39 pm
content: Ok, guess I'll have to run a phone cable down to the annexe separately.Thanks for you help

author: madires
author_rank: Super Contributor
timestamp: February 02, 2019, 08:39:35 pm
content: Or go for VoIP.BTW, most installations use dual RJ45 wall sockets, i.e. two ethernet cables.

author: Monkeh
author_rank: Super Contributor
timestamp: February 02, 2019, 10:52:16 pm
content: Quote from: madires on February 02, 2019, 08:39:35 pmOften simply because it's insane to run a single cable. Run two, if both are good, free socket!

author: Brumby
author_rank: Unknown
timestamp: February 02, 2019, 11:17:32 pm
content: If you're going to run a second cable, I'd run another Cat6 - and wire up both for ethernet use. This allows you to use either cable for digital (ethernet) traffic or analogue (phone) signals.You can then use one as a phone line by simply having the appropriate patch cable. You can buy phone cables with RJ45 on one end and RJ12 on the other.Then, if you want to move to VOIP, you can change the usage of the second line without any rewiring or changing your existing ethernet setup on the other line. Also, with two ethernet lines, you have redundancy and/or expansion - which is never a bad thing.

author: edavid
author_rank: Super Contributor
timestamp: February 02, 2019, 11:23:45 pm
content: Quote from: FrankE on February 02, 2019, 07:24:43 pmNot really, it's twisted pair. You can mix 100BT and voice on the same CAT5 or CAT6 cable and it works fine. The lightning issue is worth some thought though. Of course if the phone line is coming from an ISP provided VOIP modem, that's not an issue either.

author: Ian.M
author_rank: Super Contributor
timestamp: February 02, 2019, 11:48:02 pm
content: Ethernet signals can degrade ADSL on a pair in the same cable. However ADSL can be degraded by just about any source of RF noise, so, leaving the lightning damage issue aside, the best advice is to split it off with a filter at the demarc point so there s no ADSL signal on any of your home phone wiring and run dedicated STP cabling to the modem for it.

author: MavMitchell
author_rank: Contributor
timestamp: February 03, 2019, 01:42:09 am
content: Splitting is routinely done, although its not ideal as described above.It is limited to 100Mbps and will interfere with DSL signals as indicated.https://www.lanshack.com/QuickTreX-VoiceData-Splitter-Pair-P1564.aspx

author: edavid
author_rank: Super Contributor
timestamp: February 03, 2019, 02:37:19 am
content: Not sure why people are bringing up DSL... it seems like a red herring since OP did not mention it.

author: Monkeh
author_rank: Super Contributor
timestamp: February 03, 2019, 02:39:11 am
content: Quote from: edavid on February 03, 2019, 02:37:19 amBecause DSL is by far the most common way of getting online in the UK.

author: dave_k
author_rank: Frequent Contributor
timestamp: February 03, 2019, 03:04:03 am
content: Quote from: Invader75 on February 02, 2019, 02:04:46 pmJudging by the use of the blue and orange wire I wouldn't be using that electrician again if he cannot even identify what a "pair" is!

author: Whales
author_rank: Super Contributor
timestamp: February 03, 2019, 03:12:35 am
content: Quote from: Brumby on February 02, 2019, 11:17:32 pmN.B. not necessary. RJ12 cables will fit and click into RJ45 sockets just fine (as will a few other RJ variants). They are also pin-compatible in that the middle 4 wires of ethernet RJ45's are arranged to match common phone connector use. It's a clever design that in practice maintains compatibility.If you plan to use RJ45 sockets for anything other than ethernet: label them to hell and keep them away from normal ethernet ones. You don't want anyone blowing network cards (or worse) by plugging into a phone line.+1 to the advice of not running phone lines in the same cable jacket as anything else that doesn't have lightning protection. Ideally not even in the same bundle of cables. If you are desperate then there might be some dedicated lighting arrestor devices you can permanently install, no idea how effective they are.

author: Ian.M
author_rank: Super Contributor
timestamp: February 03, 2019, 04:07:20 am
content: Quote from: Monkeh on February 03, 2019, 02:39:11 am... and the ISPs usually supply a bundled 'kit' to domestic customers for self-installation with a combo DSL modem/router typically with four LAN ports,and a few DSL microfilters to go between phone equipment and the existing phone sockets to keep the DSL signal out of equipment that coud adsorb it or otherwise mess it up. You plug the modem/router into the DSL port of one of the filters.Done as instructed (just described), that leaves all phone wiring in the property carrying the DSL signal and picking up interference. Typically, if the house was previously wired with a lot of extension sockets, fitting a whole house DSL filter at the demarc (master socket in the UK) gets you a significant speed increase!

author: madires
author_rank: Super Contributor
timestamp: February 03, 2019, 11:18:28 am
content: Quote from: Whales on February 03, 2019, 03:12:35 amThey do, but the smaller plugs will bend the outer contacts of the RJ45 socket causing contact issues later on when inserting an RJ45 plug. Get a cheap RJ45 crimp tool and a few plugs.

author: johnkenyon
author_rank: Regular Contributor
timestamp: February 03, 2019, 12:38:06 pm
content: Quote from: Brumby on February 02, 2019, 11:17:32 pmHint 1 - RJ45 to BT431 adaptors depend on the phone line being on pair 1 (i.e. the two centre pins)Hint 2 - you can usually insert an RJ11 lead directly into an RJ45 socket - again make sure the phone line is on pair 1, and you can sometimes get away without having to install an adaptor(my UK example: I have an ADSL filter where the phone line enters the house, a short RJ11 to RJ11 lead which plugs into a Cat6 ethernet extension back to the "server room". In the server room another RJ11-RJ11 cable is used between the patch panel and the DSL modem. This also has the advantage of dropping the unbalanced "ringer" wire along the extension cable, which gives a minor boost to the DSL line rate)

author: Invader75
author_rank: Newbie
timestamp: February 03, 2019, 03:02:00 pm
content: Ok, slow down guys!This is in the beginners section.The install is done, cat6 was run underground with the rest of the utilities so I can't add another cat6 unless I just run it down there externally. Likewise with a phone line.The electrician wasn't chosen by us, he came with the people who were installing the annexe.I just want a simple solution, or answer, to the problem.Many thanks.Mr Layman ;-)

author: madires
author_rank: Super Contributor
timestamp: February 03, 2019, 04:38:39 pm
content: Do you need the phone line for a telephone or something else, like DSL for example?

author: Invader75
author_rank: Newbie
timestamp: February 03, 2019, 04:46:09 pm
content: I need a phone line for a phone and ethernet for a router. 👍🏻

author: madires
author_rank: Super Contributor
timestamp: February 03, 2019, 04:54:59 pm
content: Would a cordless phone work for you?

author: Invader75
author_rank: Newbie
timestamp: February 03, 2019, 05:06:21 pm
content: Cordless fine but probably too far away from the house for the signal to reach. Approximately 15 metres.

author: madires
author_rank: Super Contributor
timestamp: February 03, 2019, 05:12:45 pm
content: 15m shouldn't be a problem for DECT. Another solution would be VoIP. The telcos are migrating their telephone networks to VoIP anyway.

author: soldar
author_rank: Super Contributor
timestamp: February 03, 2019, 05:15:27 pm
content: Quote from: Invader75 on February 03, 2019, 03:02:00 pmNo conduit? Is that even legal?There is weatherproof phone cable, of course. You can just run a new line.Quote from: Invader75 on February 03, 2019, 03:02:00 pmThe electrician was not chosen by you but what you wanted done was presumably specified by you. The time to ask for simple solutions was when you specified the work to be done. Now the simplest solution is probably to just run another cable.

author: Invader75
author_rank: Newbie
timestamp: February 03, 2019, 05:17:06 pm
content: Ok, thanks. I think what's best is to stick to using the cat6 for internet only. Then I'll see how the DECT phone gets on or alternatively switch to VoIP.

author: Invader75
author_rank: Newbie
timestamp: February 03, 2019, 05:24:42 pm
content: Quote from: soldar on February 03, 2019, 05:15:27 pmChill out fella. Nobody's looking to score point or start an argument. I'm just after some "Beginner" advice. Which is why I posted it in the "Beginner" section.Yes, it has conduit. The reason why a phone cable wasn't installed was because it couldn't be further from my mind as I never used a regular phone line. This is an annex for my elderly and disabled parents. It was an oversight on my side and not something they would've been thinking about.

author: Ian.M
author_rank: Super Contributor
timestamp: February 03, 2019, 07:48:32 pm
content: You f---ed up by not specifying two cables in seperate conduits, (not that you knew that) but the electrical subcontractor also f---ed up by not installing the conduit with mousing line through it to pull in more cables. Usually, you can only mouse a cable through if there is no more than one 90 deg swept bend in the conduit, (or swept bends totalling 90 deg), otherwise there's too much friction, so if neither building has a cellar that would have required an access pit and cover. It only has to be big enough to get your arm down, with enough room for a straight pull on the mousing line.How to fix it? Well as its a dwelling for disabled elderly, a high reliability telephone connection that will work if there's a power cut is a must for emergency use. You may in the future need to install an elderly alert system, which *WILL* need a wired connection to its base statiion and has limited guaranteed wireless range. A DECT cordless isn't reliable enough, especially at extended range, nor are VOIP systems reliable enough, even if you put the DECT basestation or the VOIP adapter, router and your ADSL modem/router on UPSes.If you are willing to settle for low performance and reduced security on the network, you may be to get away with a pair of 2.4Ghz WiFi access points with directional antennae acting as a wireless bridge between two wired network, to free up the Cat6 for the phone line. However unless the annex is an outbuilding far from the main building, iit will probably be cheaper and simpler to run an appropriately rated four wire exterior phone cable. Use the armoured direct burial type if it has to go under any paths etc. or run low down on exterior walls, or run on the outside of boundary walls etc. or regular exterior cable if you can run it so it isn't likely to get damaged.

author: Invader75
author_rank: Newbie
timestamp: February 03, 2019, 09:36:26 pm
content: Yep, fair points. Last thing on my mind when taking care of a rather big build. Don't use landlines, and haven't for over 15 years so it slipped my mind. Will install a separate one and look at Alert Systems.

author: edavid
author_rank: Super Contributor
timestamp: February 04, 2019, 12:33:40 am
content: Quote from: Ian.M on February 03, 2019, 07:48:32 pmIn the US, most elderly alert systems are just cell phones with an emergency button. Is it different in the UK?QuoteAn Orbi set should give good enough performance at 15m distance.

author: Ian.M
author_rank: Super Contributor
timestamp: February 04, 2019, 01:16:45 am
content: As eDavid has just pointed out I may be out of date on current practice and method of communication to the monitoring company for elderly alert systems, so PLEASE DO YOUR OWN RESEARCH. When parents are involved, second best is not good enough. I'd still advise a landline and some basic wired phones just to have reliable emergency communications - no critical reliance on handsets being charged and not mislaid and they are much simpler for the less able to operate as long as they've still got reasonable use of one hand.

author: tooki
author_rank: Super Contributor
timestamp: February 05, 2019, 03:10:10 pm
content: Quote from: Invader75 on February 03, 2019, 05:24:42 pmIf the conduit is big enough, it should be no problem to fish another cable through it, even if it’s just a thin Cat 3 or something, just for the phone.

author: richard.cs
author_rank: Super Contributor
timestamp: February 05, 2019, 07:46:15 pm
content: Quote from: edavid on February 04, 2019, 12:33:40 amYou'll be wanting EN 50134 :-)Alert systems here need to comply to that standard, which does allow both a PSTN and cellular backhaul but mostly disallows VOIP. Usually there's a box connected to an ordinary phone line with a big red button on it that can also act as a speakerphone, fancier systems have fallback to cellular if there's a fault with the line. Usually there's also a wireless portable alarm button but it has to use a dedicated slice of spectrum for reliability - no ISM bands allowed.