Unoffical empeg BBS

Quick Links: Empeg FAQ | RioCar.Org | Hijack | BigDisk Builder | jEmplode | emphatic
Repairs: Repairs

Topic Options
#156423 - 21/04/2003 16:09 RJ11 & RJ45 in the same housing?
jbauer
veteran

Registered: 08/05/2000
Posts: 1429
Loc: San Francisco, CA
I'm trying to figure out how to wire my place... I have 2 twisted pairs going to each outlet so I can wire each jack for either an RJ11 telephone or an RJ45 Ethernet outlet. It seems strange to me that no one has come up with a jack that you can plug either plug into, since they are both wired the same... (1,2,3, & 6) Of course, you'd need to feed the other side properly, but it would make things a LITTLE easier...

Or is this available somewhere??

- Jon

Top
#156424 - 21/04/2003 16:24 Re: RJ11 & RJ45 in the same housing? [Re: jbauer]
robricc
carpal tunnel

Registered: 30/10/2000
Posts: 4931
Loc: New Jersey, USA
You can make an adapter yourself.

Make the wall plate RJ45. Then, if plugging in a phone, make a cable that has RJ45 on one end and RJ11 on the other.
_________________________
-Rob Riccardelli
80GB 16MB MK2 090000736

Top
#156425 - 21/04/2003 16:32 Re: RJ11 & RJ45 in the same housing? [Re: jbauer]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31596
Loc: Seattle, WA
Just get jack panels with inserts, and put in whichever jack insert you want into that panel. Or it can have two inserts, with both simultaneously wired, and just use whichever you've got patched in at the central switching location.

Honestly, though, you should be wiring four pairs (full cat-5) to each outlet...

Where I work, we have three sets of four pairs (three cat-5 connections) to each outlet. Two full four-pair LANs, and then one phone and one optional modem on the remaining cat-5 cable. The phone needs two pairs because it's a multiline company phone system.
_________________________
Tony Fabris

Top
#156426 - 21/04/2003 16:35 Re: RJ11 & RJ45 in the same housing? [Re: tfabris]
jbauer
veteran

Registered: 08/05/2000
Posts: 1429
Loc: San Francisco, CA
I don't think the place (I haven't moved into it yet, just planning ahead) has a full cat-5. I believe it has 2 twisted pairs. Why would you need to wire more than just the ones you need? I see your smiley, but is there any reason to have it fully wired?

- Jon

Top
#156427 - 21/04/2003 16:42 Re: RJ11 & RJ45 in the same housing? [Re: jbauer]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31596
Loc: Seattle, WA
has a full cat-5. I believe it has 2 twisted pairs.
I thought a full cat-5 was four twisted pairs, making the combination of those two sentences a non-sequitr. I could be wrong about that. Edit: Just re-read your sentence. You said DON'T THINK not THINK. Sorry. Didn't realize you were referring to existing wiring. Thought you meant you were doing the wiring yourself.

Anyway, the advantage? If you have four pairs instead of two, you can run 10/100 LAN and two telephone lines telephone together on the same wire.

I've been in enough situations where I run out of in-wall wires too fast and I'm just an advocate of over wiring the in-wall stuff from the start, to plan for future expansion. Someday you might want to run gigabit ethernet across the house. Or maybe steal a few pairs for running an s-video connection across the house. Or something like that. I'm just saying, when doing the basic wiring, it's better to have more wires than you need than it is to run out of wires after the plaster is in place.

_________________________
Tony Fabris

Top
#156428 - 21/04/2003 16:46 Re: RJ11 & RJ45 in the same housing? [Re: tfabris]
jbauer
veteran

Registered: 08/05/2000
Posts: 1429
Loc: San Francisco, CA
I agree with you completely. Problem is, the plaster IS up. This place was built in 1999, but I don't think they wired it with a full CAT-5 - believe that? I'm pretty sure it's just 2 twisted pairs going to each jack. So that leaves me with a choice... hard wired Ethernet or hard wired telephone at each jack...

- Jon

Top
#156429 - 21/04/2003 16:47 Re: RJ11 & RJ45 in the same housing? [Re: tfabris]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31596
Loc: Seattle, WA
As a follow-up... If you're talking about a place that has existing wiring...

When you have two pairs in the wall like that, you often are talking about a system where all the jacks are wired together for two phone lines only. In that case, you can't run ethernet across those wires. You can't plug multiple ethernet devices into the same wire-stream without a hub to negotiate among them. If that's the case, you could look into HPNA cards...
_________________________
Tony Fabris

Top
#156430 - 21/04/2003 16:51 Re: RJ11 & RJ45 in the same housing? [Re: tfabris]
jbauer
veteran

Registered: 08/05/2000
Posts: 1429
Loc: San Francisco, CA
Hm. I'm going to have to do some serious testing when I move in.

- Thanx
- Jon

Top
#156431 - 21/04/2003 18:00 Re: RJ11 & RJ45 in the same housing? [Re: jbauer]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
RJ11 is a 4-conductor spec. RJ45 is 8-conductor. Perhaps you're thinking of RJ12, which is 6-conductor. I have seen a number of contractors use RJ45 jacks for RJ12 termination, I suppose just to make things simpler, but that doesn't solve your problem.

Certainly the common ethernet specs use pins 1,2,3 and 6 on an RJ45 cable, but I don't know where you get that RJ12 does the same for phones. IIRC, and I may not, it uses 3 and 4 for line 1 and 2 and 5 for line 2. I assume that it uses 1 and 6 for line 3, but I don't know that at all. However, even if I'm wrong and RJ12 uses pins 1,2,3 and 6, they wouldn't be the same as pins 1,2,3 and 6 on RJ45, They'd be the same as pins 2,3,4 and 7. Remember that the RJ12 connectors are going to be set one in on either side from RJ45.

That being said, the center pair in ethernet applications is unused and IIRC that the center pair is line 1 for phones, then you could conceivably wire both phones and ethernet to the same jack. Of course, you'd only be able to use one at a time without an adapter of some nature, and I have no idea if the voltage over the center pair might damage your NIC or computer.

The real thing is that you're going to have to rewire it anyway in order to get any ethernet, as Tony pointed out. Why not go ahead and do it right?

If you know where the wires are running to, you might be able to pull them through the walls and attach a nylon string to them as you do. You could then use that to guide a fish tape through the walls to pull real cabling.
_________________________
Bitt Faulk

Top
#156432 - 21/04/2003 18:46 Re: RJ11 & RJ45 in the same housing? [Re: wfaulk]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31596
Loc: Seattle, WA
I think you're right about the pinouts for an RJ12 plug, Bitt.

And I'm sure you know this, Jon, but if one attempts to plug an RJ11 or RJ12 plug into an RJ45 jack, it may seem to fit with a little trouble, but you'll bend the outer pins in the process. So you'll need to use the right jack for the right plug.
_________________________
Tony Fabris

Top
#156433 - 21/04/2003 18:51 Re: RJ11 & RJ45 in the same housing? [Re: jbauer]
oliver
addict

Registered: 02/04/2002
Posts: 691
just put the phone lines to each room, and use wireless ethernet for your network problem solved. maybe one 1 or 2 rooms with ethernet just in case you need some bandwidth for something
_________________________
Oliver mk1 30gb: 129 | mk2a 30gb: 040104126

Top
#156434 - 21/04/2003 21:28 Re: RJ11 & RJ45 in the same housing? [Re: wfaulk]
jbauer
veteran

Registered: 08/05/2000
Posts: 1429
Loc: San Francisco, CA
Bitt,

Wait a sec. Ethernet uses 1,2,3 and 6, so I don't need to re-wire if I only have 2 twisted pairs... right? Ok, I must have been wrong that RJ11 uses the same pins...

- Jon

Top
#156435 - 21/04/2003 23:05 Re: RJ11 & RJ45 in the same housing? [Re: jbauer]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31596
Loc: Seattle, WA
Wait a sec. Ethernet uses 1,2,3 and 6, so I don't need to re-wire if I only have 2 twisted pairs... right?
Well, it depends on how those wires are hooked up inside the walls. If they connect directly to each other (for instance, if all of the jacks in the walls are connected to the same wires), then you need to rewire.

If you have a completely separate run of 2-pair cable for each and every jack in the house and they all converge in a central location such as a wiring closet, then you can put RJ45 jacks at each end of each of these existing wire runs, and they will work as ethernet cables as long as you get the right pairs on the right pins at the ends of the wires, and you put a hub where all the wire runs converge.

But if all these jacks are wired to each other and the wires are all connected together (essentially making them into one long wire with multiple cut-in points at each wall socket), then they are wired for a telephone and cannot be used for ethernet.

I'm just confused about how this house is wired. From your description, it sounds like a standard four-wire telephone system with standard two-line analog telephone wiring. I can't imagine someone wiring it to be ethernet-capable with only two pairs.
_________________________
Tony Fabris

Top
#156436 - 22/04/2003 01:30 Re: RJ11 & RJ45 in the same housing? [Re: tfabris]
andym
carpal tunnel

Registered: 17/01/2002
Posts: 3996
Loc: Manchester UK
In reply to:

you can run 10/100 LAN and two telephone lines telephone together on the same wire.




Or two LANs, I did that in my old house, one used to go from my cable box in the living room to my router in the study and the other went from the switch in my study back down to the living room so I could plug my laptop in.
_________________________
Cheers,

Andy M

Top
#156437 - 22/04/2003 06:09 Re: RJ11 & RJ45 in the same housing? [Re: andym]
djc
enthusiast

Registered: 08/08/2000
Posts: 351
Loc: chicago
Of course, you'd only be able to use one at a time without an adapter of some nature, and I have no idea if the voltage over the center pair might damage your NIC or computer.

you definitely want to be careful here. even if your NIC is wired to ignore those pins that it doesn't use, the -48VDC ring voltage on an analog telephone line will quickly fry a NIC if wires get inadvertantly shorted or crossed. beware.

--dan.

Top
#156438 - 22/04/2003 07:30 Re: RJ11 & RJ45 in the same housing? [Re: jbauer]
jmwking
old hand

Registered: 27/02/2003
Posts: 776
Loc: Washington, DC metro
One other thought - most household phone wiring is Cat-3, not Cat-5, so you'll be limited in bandwidth, regardless of connector types.

-jk

Top
#156439 - 22/04/2003 08:47 Re: RJ11 & RJ45 in the same housing? [Re: jmwking]
lectric
pooh-bah

Registered: 20/01/2002
Posts: 2085
Loc: New Orleans, LA
Dammit, you beat me to it. As JK said, telephone wiring does NOT have enough twists to get away with 100BT ether. in fact, many versions of phone wires have NO twists at all, which is a BAD THING. Look at the ends of the wire coming out of the shielding. If they're flat, you're in trouble. If they're twisted, it may work until your wife turns on her hair dryer or someone uses the blender.

Top
#156440 - 28/04/2003 00:34 Re: RJ11 & RJ45 in the same housing? [Re: lectric]
jbauer
veteran

Registered: 08/05/2000
Posts: 1429
Loc: San Francisco, CA
Wanted to post an update:

I moved into the place that I was talking about in this thread. The wiring was a full 8 wire CAT-5 going to all of the jacks. The RJ-11 jacks were already hooked up using 4 of the wires (why? i don't know, you can do that with 2!). 4 other wires were completely unused.

So I've installed 5 of the jacks with RJ-45 and Ethernet. Wired them for 1,2,3,6 and shazam - Ethernet all around the house! I put my dsl, firewall and switch in the closet and it's working like a champ. Speed seems great, although I haven't tested large file transfers from PC to PC. The dsl is feeding the PCs as fast as if it were hooked up directly to a PC...

Thanks for the advice given previously on this thread. I didn't know what I was getting into in this place and I was as prepared as I could have been.

- Thanx
- Jon

Top
#156441 - 28/04/2003 10:18 Re: RJ11 & RJ45 in the same housing? [Re: jbauer]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31596
Loc: Seattle, WA
Too cool, Jon! Congratulations.
_________________________
Tony Fabris

Top
#156442 - 28/04/2003 10:22 Re: RJ11 & RJ45 in the same housing? [Re: jbauer]
peter
carpal tunnel

Registered: 13/07/2000
Posts: 4180
Loc: Cambridge, England
I moved into the place that I was talking about in this thread. The wiring was a full 8 wire CAT-5 going to all of the jacks.
[envy]

I wish they'd thought of that when they were building my house in 1860...

Peter

Top
#156443 - 28/04/2003 13:09 Re: RJ11 & RJ45 in the same housing? [Re: jbauer]
lectric
pooh-bah

Registered: 20/01/2002
Posts: 2085
Loc: New Orleans, LA
Niiiice, very unusual, but nice.

Top
#156444 - 29/04/2003 09:35 Re: RJ11 & RJ45 in the same housing? [Re: peter]
genixia
Carpal Tunnel

Registered: 08/02/2002
Posts: 3411
I wish they'd thought of that when they were building my house in 1860...

LOL. I feel that pain too.

They didn't even have the decency to predict that a basement->attic channel might be useful, so running *anything* is a pain.
_________________________
Mk2a 60GB Blue. Serial 030102962 sig.mp3: File Format not Valid.

Top
#156445 - 12/05/2003 21:41 Re: RJ11 & RJ45 in the same housing? [Re: lectric]
drakino
carpal tunnel

Registered: 08/06/1999
Posts: 7868
/me begins digging up old threads while he catches up a bit.
Niiiice, very unusual, but nice.

My place is coming with Cat 5 for phones or an ethernet network. Several jacks in the house will acually be hiding 2 RG6 cables and 2 Cat 5 cables behind the panal for me to do whatever with. This is actually standard on every house in the area now, as they are running a deal where the local home theather company comes in and does the wiring during construction for free.

Top