I've got a home network with cat5 cable running from a central hub to multiple outlets in each room. I want to use one of the outlets in each room for phones and therefore need some rj11 to rj45 converters. There seem to be three different types of converter available:
Secondary PABX Master
As my plan is just to wire one end of a cat5 cable into my main telephone point via the pull off portion of the BT socket, plug the other end into the nearest cat5 outlet and use the patch panel with five ports wired in parallel to connect that outlet to all the other(4) outlets that I want to put a phone on, what sort of converters do I need ?
It is not a wise move at all! You are making all sorts of future problems and in any case it will not meet the rules for connection to BT lines. Do the job with proper spec. CW1308 cable instead.
Secondary is just fine, and is what I've used in my setup. Yer PABX one has a surge arrestor and ring capacitor (here in the UK we "filter" off the alternating ring current onto a separate wire from the "voice" wires); the PABX has, if I recall aright, the ring capacitor. Since your standard BT master socket has the ring capacitor and bell cap already, simple "wire-only" secondaries are what you want.
To preserve the flexibility of my patch panel, I have the phone points "buswired" by using 3-way female RJ45 couplers, such as RS partnum
186-3098. Then standard patchcords at the patch panel take the incoming phone line, with (for example) the two front connectors used for the "bus" and the back one for each "drop". LAUs (Line Adaptor Units, fancy name for the RJ45-to-BT-socket converter) I use only in the rooms where the phones plug in - at the "feed it into the patch panel" end I did roughly what you describe (well, to tell the truth, I butchered some BT-plug-bearing wire, plugged that end into the relevant BT socket, e.g. the two "analogue" ports of the Home Highway and the front port of the analogue-now-ADSL master, and in a little adaptable box with small terminal block wired to suitably butchered RJ45 cables, so that you end up with the LAUs in each room being "straight-through" extensions of the BT sockets.
On the ADSL side, I got a Solwise faceplate for the old BT master box (honest, it was the existing BT master box ;-) which has the ADSL filter configured so that the BT front-socket and the put-your-phone-extension-wiring-here point are both post-filter, and just the RJ-11 socket on the front is "prefilter". I then ran the pre-filter up to the patch panel on a separate way, so that the ADSL "modem" can go wherever I want it to, while all the phones on that line
- whether they go through the patch panel or are hardwired extensions predating our living in this place - are all behing the ADSL filter.
CAT5 is routinely used for voice and data. You can even run voice and ethernet over the same CAT5. Using CAT5 for everything can make for a far more flexible setup.
Hmmm... better tell that to all the large offices in the land, which routinely run their phone systems and LAN wiring over the same set of premises cabling. There's a word for it somewhere... on the tip of my tongue... ah yes - "structured wiring".
Data cabling is considerably "higher spec" than phone; historically, the whole idea of Ethernet-over-twisted-pair came about in the early 80s with the dawning realisation that (a) pulling new lengths of gert thick yellow coax ready for vampire taps throughout existing buildings was expensive and awkward, and (b) there were wires running to just about all the places you wanted to put Pee Cees and similar already, being the phone points; and these wires moreover were twisted-pair, giving you some hope of noise rejection if you ran a differential signal down them... ooh, and the cabling they were bundled in might even have spare pairs!
I well remember early internal presentations from the network research mob in HP in 1985/86, showing the feasibility of the then-crazy idea of running network traffic down Plain Old Telephone wiring, at the then-fantastical data rates of 1 Mbit/s or even higher. The common twist rate then made higher rates a bit iffy - yer classic phone cable is/was sthg like "Cat 3" or "Cat 2". The shift to higher twist rates, more tightly-specced twists, different twist rates in different pairs, and all that good stuff which makes Cat5/Cat6 suitable for 100MBit and gigabit working, is all about making building wiring fit for high data rates, while keeping it pin-for-pin compatible with olde-worlde US telco style. (That backward compatability is why we have the slightly-daft-for-data business of having pins 3&6 of an RJ45 being one pair, with 4&5 within, rather than keeping all the pairs adjacent in the "logical" 1-2, 3-4, 5-6, 7-8 style, which would allow twists to be more reliably maintained close up to the connector).
In another 5-10? years, larger business premiseses will have swapped over to Voice-over-IP for nearly all telephony (but retaining some "real" PABX and direct-lines for backup usage, one hopes); home phone service will need to stay POTS-compatible for a while longer, but I expect to see telcos encouraging their customers to move to "IP dialtone" or whatever idiot marketing designation they come up with, to simplify their network admin - right now they're having to run exciting mixtures of SS7 and IP-based stuff, mostly with an ATM core (anyone remember "ATM to the desktop?" Hasn't happened, though ADSL is (in the UK) "ATM to the demarc"!).
And to return back to the original posting, the glorious good sense of the BT master socket design (the NTE5) which the OP is wiring into is to separate all the internal-extension stuff from the BT side. This separation allows BT to be rather more relaxed about "the rules for connection to BT lines" - if the punter has a problem when the NTE5 faceplate is in place, but not when the phone's plugged into the "deeper" NTE5 socket, the customer's internal extension wiring is at fault, and it's Major Shrug And Callout Fee time.
I did something pretty similar, except I ran the butchered BT-plug-bearing wire directly into an RJ45 plug, to plug into the patch panel.
One thing is that I couldn't find any standard connection mapping a 4-wire phone connection onto an 8-wire Cat 5 cable. I tested out 3 different makes of LAU I found around the office, and they were all different mappings. If you buy a set of LAU's, you might want to make sure you get all the same make, or you start having to ensure you have the same type at each end of the Cat 5 cable run.
The difference is that mssters have surge arrestors and reconstiute ring voltage with a resistior and capacitor, PABX are teh same but have noi surge arrestor, and slave have bothing - they need a three wire circuit
CAT 5 is fine phone cable. It may not be to BT spec, but it works better than theirs.
Indeed. It is conventional to use different pairs for phone and ethernet.
Its fine for PABX work, and I do this here, its not strctly kosher to connect such to BT, BUT I re-installed my ISDN hookup extending the incoming line to the master socket using cat 5, and its flawless, and BT couldn't really give a damn.
Exactly! The point being that it is fine if done by someone who knows in detail what is required and has the equipment to do it. My answer was directed at someone who was unlikely to have the equipment or expertise to do the job to the sort of standard that one would expect from a professional installer in an office environment. Using separate phone cable is much easier in domestic circumstances for most people.
Which "rules" are these ? When did CW1308 become magically better than Cat5 ? Why do you bring up "future problems" other than to spread FUD ?
I don't personally like structured cabling over Cat5, for the simple reason that the dangling socket adapters are ugly and damage prone. Apart from that though, there's just no reason to favour CW1308 over any reasonably competent work with Cat5.
A very constructive post. Are always as forthcoming? You miss the point entirely. The advantage of using the proper twisted pair cable is that it is easy to install without specialist tools or test gear by anyone with very basic skills and it should work without any problem. In a normal domestic situation that seems to me to be the best answer. If you use the so called "telephone cable" sold by the sheds etc. you will probably end up with untwisted that is prone to interference. Using the proper cable can make a lot of difference. Using structured cabling in a domestic environment seems OTT particularly if you don't have proper tools and test gear. The question asked made it quite clear that the OP did not have either.
Hmm... my reading of the OP's post was that there was existing structured wiring in place. To quote:
"I've got a home network with cat5 cable running from a central hub to multiple outlets in each room. I want to use one of the outlets in each room for phones and therefore need some rj11 to rj45 converters."
While "central hub... multiple outlets" could be read literally as a cheapie 8port hub and trailing patchcords blutac'd to the ceiling, the words, and subsequent clueful phrasing (including the giveaway phrase "use the patch panel with five ports wired in parallel") suggested the presence of a, umm, patch panel, with fixed solid-core Cat5. Yes, there's a minority of geeks who have their houses wired this way, but they're over-represented in this newsgroup. The OP seemed perfectly clueful enough to ask a specific question to fill a specific gap in otherwise adequate understanding - "what are these telco geezers trying to say with their 'master', 'PABX', and 'secondary' words?", so a direct answer, with this-is-wot-I-did-to-preserve-patch-panel-flexibility as an add-on, seemed like a more appropriate and useful response than "don't do that, put in dedicated phone extensions using CW1308 instead".
No _you_ miss the point entirely. The OP already has a Cat5 install. we're not talking about old bits of bell-wire here.
Incorrect. CW1308 is a solid core for use in IDCs. The specialist tool may be only tenpence for a one-shot plastic one, but it's still better than the screwdriver that so many DIYers use and is an essential install tool.
My Krone tool is also the same one I use for either Cat5 or CW1308. Comparing tools is a red herring on this issue.
Maybe - it's what I use. Byt the OP doesn't have a "normal" situation, he has structured cabling over Cat5. That's a perfectly valid way to do it.
end up with
If you use damp string it will be even worse. But no-one is suggesting that.
What test gear do you need for Cat5 that you don't also need for CW1308 ? TDR is _nice_, but it's overkill even for 100baseT in a run the size of a domestic house.
Between PABXs, or to the desks ? There are plenty of big offices where it will still be some time before VoIP is doing the in-office equivalent of the local loop.
To the desks. All the phones are marked "IP phone."
And plenty where it's alread a done deal. The PABX usually has a router that decides if the voice traffic is going to head out to PSTN or if it can be routed to the few locations that are already on IP phones.
I also see that Draytek is doing a home VoIP/DSL router, which looks interesting.
I deal with things differently here at present. I have a problem with running copper arounf the building because of the age and the thin plaster on the walls, and the listed status. So I use copper within the office only, the rest of the place is served by DECT and 125Mb/s
Same here, BT engineer was happy to take a new line and my existing ADSL unfiltered connection striaght into CAT5 (in fact it was their old bit of CAT5 which was installed for ISDN)
I am in the process of doing exactly this sort of thing - Cat5 for phone and data. I also had the issue of finding a suitable adapter to go into the wall RJ45 ahd take a phone plug. There is a suitable (and CHEAP at £2.95) secondary balun available from
formatting link
puts the four main lines (as opposed to only two for some secondaryies) over the Cat5 in the following arrangement:
My plan is simply to punch down the wiring from the BT Master onto a number of sockets on a patch panel, then use patch leads to feed phone through to whichever wall sockets I want.
Guess you have to be careful about REN, but other than that I am not aware of any major issues with doing this.
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