Using Cat 5 wire for telephones (and more)

Discussion in 'Mac Accessories' started by Le Big Mac, Dec 4, 2005.

  1. Le Big Mac macrumors 68020

    Le Big Mac

    Jan 7, 2003
    Washington, DC
    So, I've bought a new house (well, a very old house), and I'm having some work done on it, which includes getting Cat-5 and other comm. wiring installed.

    I was thinking of dispensing with phone wiring, since I imagine in 5-10 years phones (cat-3 wiring) will be irrelevant and we'll be on VOIP. Instead, I figured I could get each room wired for 2 or 3 cat-5 (ethernet) jacks. In the meantime, I would use an adapter so I could plug a phone into the ethernet jack. Then at the patch panel in the basement, I'd use the same jack, and wire the phones together.

    1) Does that adapter exist? I think it would be an RJ11 to RJ45 adapter.
    2) Any problems with this plan? Obviously I'd be careful about which jack is for which, because I imagine that the ring signal wouldn't be so good to send to a computer.
  2. belvdr macrumors 601

    Aug 15, 2005
    Use CAT5 and then connect it to RJ11 jacks. THen, when you want to convert to RJ45, you just need to replace the jack.

    On the other hand, you can use the RJ45 jack and plug the phone directly into it. The RJ45 jack is bigger, obviously, but it won't hurt anything.
  3. Laser47 macrumors 6502a


    Jan 8, 2004
    Regular phone connectors will fit in the ethernet jacks, so you could just wire the jacks to accept a phone connection, I dont think anycompany would sell this because it could cause confusion when connecting phones. Also some people use a Cat5 cable to carry both phone and data at the same time. Where they have 1 RJ45 jack and a RJ11 jack connected to one Cat5 cable. This is since Cat5 uses 4 Twisted pairs (8 wires) and 100mbps ethernet only requires 2 twisted pairs (4 wires), and a 1 line phone only uses 1 pair (2 wires). So if you wanted you could just use 1 single cat5 cable to carry a 2 phone lines, and one data line, or 2 data lines. If you wanted to use power over ethernet however you would need 3 pairs for ethernet.
  4. DMPDX macrumors 6502

    Dec 4, 2005
    I Know A Little

    I remodeled my house about one year ago and had the same thoughts that you are having now. I had the choice of cat3 cat5 or cat6 for my data and phone line wires. I went with cat5 for my data lines (ethernet) and cat5 (i think) for my phone lines along with a catv line for each wall plate. I had a pro come and install and wire the whole house but he said I could have up to 8 ports on one face plate in the design that I chose. So far it works fine. I cant tell the difference between cat5 and cat6 so I think I should be good for the next 5-10 years. I' go for the dual cat5 and cat6 if you can afford it. I hope your decicion finds itself a good spot in your new, or "born again" home.:)
  5. jaw04005 macrumors 601


    Aug 19, 2003
    When we built our new house, we had two CAT 5 drops at each outlet. It's come in very hand for our uses.
  6. SpaceMagic macrumors 68000


    Oct 26, 2003
    Cardiff, Wales
    In work we do this.

    You just need an RJ45-Cat5 converter little thing.
  7. Le Big Mac thread starter macrumors 68020

    Le Big Mac

    Jan 7, 2003
    Washington, DC
    Thanks, all.

    A couple of follow-ups:

    1) I tried plugging a phone jack into a cat5/RJ45 jack and it didn't seem to fit so well. I was actually surprised. Was I doing something wrong?

    2) For those who were building, about how much did you get charged per drop? I'm sure whatever it is seems like way too much.:rolleyes:
  8. belvdr macrumors 601

    Aug 15, 2005
    The RJ11 jack will fit lopsided in the RJ45 jack, but it should still work.
  9. Makosuke macrumors 603

    Aug 15, 2001
    The Cool Part of CA, USA
    RJ-11s don't fit all that well into RJ45s (I've seen the pins in the port bent badly enough to cause it not to work properly), so I'd just get either the wall wired with RJ-11 jacks or your phone cord wired with RJ-45 on one end. It's not like it'll cost much to replace them if and when the time comes.

    Personally, I'd do the wall jacks as RJ-11 so you won't accidentally plug your phone into an Ethernet port or vice versa--less confusion is good. Also, is the voltage on phone wiring high enough to damage an Ethernet port, or are they protected against that? If so, then it's definitely worth protecting yourself by wiring the wall plates RJ-11.
  10. belvdr macrumors 601

    Aug 15, 2005
    The voltage will burn out an ethernet card. So you're right that if you're not sure you'll remember which are phone jacks that you should put RJ11 jacks there instead.

    As for the fit, our entire company (110,000 people) uses RJ45 jacks for all phones with no issues. I guess it depends on who is doing the plugging/unplugging. :)
  11. Arcus macrumors 6502a

    Dec 28, 2004
    of my hand will get me slapped.
    Why not just use cordless phones that work with a base station phone. Place the base near the dmark and put the other cordless phones wherever you want. No wires at all.
  12. Le Big Mac thread starter macrumors 68020

    Le Big Mac

    Jan 7, 2003
    Washington, DC
    I think that most corporate phone systems use RJ45 jacks and a PBX system, not the home RJ11 type.

    At a minimum I'll mark the jacks carefully. I'd rather not have to repunch them all in a few years. And I'd like the flexibility in the meantime.
  13. belvdr macrumors 601

    Aug 15, 2005
    Ours is PBX, no doubt, but the phones have RJ11 connectors and the jacks are RJ45. Either way, enjoy the quest. :)

    I think the OP's goal is to be able to have Ethernet jacks available for future use, in addition to the current use for phones.
  14. Le Big Mac thread starter macrumors 68020

    Le Big Mac

    Jan 7, 2003
    Washington, DC
    What I'm trying to do is two things:
    1) Avoid rewiring in the future (i.e., upgrade cat-3 to cat-5)
    2) Avoid re-jacking in the future (i.e., convert RJ-11 to RJ-45)

    The first is pretty easy--use Cat-5 (or Cat-6)--it's really the second that's at issue. I'm figuring it's got to be easier to have RJ-45 jacks installed, but then use an external converter to plug in the phones. sounds like some people just jam the phone jacks in the RJ-45 and it will work (assuming proper connections at the patch panel).

    I also have found these:

    RJ45 to RJ11, which may be exactly what I need--I can plug a phone into them. Buying one of those for $6 has to be worth the time/labor/cost instead of rewiring/rejacking down the road. That is, assuming they work as it appears they would.
  15. Papa-georgio macrumors newbie

    Dec 16, 2005

    I'm wondering if anyone out there knows how wire a cat 5 cable to a RJ 11 plug?
  16. degmsb macrumors newbie

    Jan 16, 2010
    I know this post is old but I have a similar situation I was wondering if someone could help with.

    I just bought a home and it is wired with cat5e.

    I had my att dsl service set up to work without
    a local phone line.

    All the cat5e wires run to a closet. The home
    does not have any phone jacks. In the closet there is a cat5e wire labeled phone master bedroom, but in the master bedroom the only thing on the wall is a cat 5 box.

    I believe it is wired to handle data and phone over the same
    cat5e wire. Is this possible?

    From the closet if I plug the cat5e wire labeled master bedroom phone into the local Ethernet port on my dsl modem then connect my computer in the master bedroom to the cat 5 box I get a local connection. I just can't get on the internet.

    Anyone got any ideas on how I can trouble shoot this to get
    on the internet?

    By the way I can't connect the phone wire to my 2wire dsl modem/router becasue it is a cat5e wire for phone. The modem takes a normal phone wire. Is there and adapter?
  17. tonyled macrumors member

    Sep 4, 2009

    take the faceplate off the jack and examine the wiring and compare it to cat5 standards
  18. balamw Moderator


    Staff Member

    Aug 16, 2005
    New England
    Assuming there are connectors on both ends, check them both. They should be the same. I had a similar issue in a previous house where the Cat 5 was terminated only on one end and was wired using a different standard than what I had used in the closet.

  19. tonyled macrumors member

    Sep 4, 2009

    yeah, i meant to say jackS

    thanks for the correction

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