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uniqs
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junitas
@104.2.189.x

junitas

Anon

wiring ethernet with 3 twisted pairs... result?


Previous homeonwer remodeled and just dropped one Cat6e to each room... very frustrating. Need to figure out an optimal layout for phone and network using the existing wire. I know I can get 10/100 with just 2 pairs, and that I need 4 for 1000. However, I only need 1 pair for the phone... meaning I have an extra pair.

So, my question is what "would" happen if I wired 3 pairs for the ethernet instead of 2? Would I see a bump in speed? No difference at all? More interference?

I've done a lot of network installations, but I've always just gone with the book. I can't seem to find ANYTHING online about this, even if it's just an explanation of why you need 2 or 4 twisted pairs. Does anyone know what would happen? Would just like a view of the details behind this for my own edification.

Thanks,
junitas

shdesigns
Powered By Infinite Improbabilty Drive
Premium Member
join:2000-12-01
Stone Mountain, GA

shdesigns

Premium Member


It will work 100mbit with 2 pairs. You may get better noise performance with the other pair connected, but it still will only connect at 100mbit.

Kilroy
MVM
join:2002-11-21
Saint Paul, MN

1 recommendation

Kilroy to junitas

MVM

to junitas
Here's a wiring diagram for 1GB ethernet. As you can see all eight of the wires have a purpose.

koolman2
Premium Member
join:2002-10-01
Anchorage, AK

koolman2 to junitas

Premium Member

to junitas
If you can find 1000-BaseTX gear, you can run gigabit over 2 pairs on Cat6. You'd basically need a switch that supports both TX and T for this, though. This equipment didn't really take off, and some gear that isn't actually TX is advertised as such in error.

YMMV

»en.wikipedia.org/wiki/Gi ··· 0BASE-TX
Bink
Villains... knock off all that evil
join:2006-05-14
Colorado

1 recommendation

Bink to junitas

Member

to junitas
If possible, I recommend killing POTS (it’s almost dead anyway), keeping your sweet Cat 6e and doing VoIP instead.

Junitas
@104.2.189.x

Junitas to koolman2

Anon

to koolman2
Koolman2:

Interesting... didn't even realize T and TX were different. Thanks for the additional insight, looks like it's mostly enterprise gear and beyond what I probably want to install given my set-up, though a one time cost to be able to run 1000 on 2 pairs may be worth it.

Best,
Junitas

koolman2
Premium Member
join:2002-10-01
Anchorage, AK

koolman2

Premium Member

Remember, though, that when 10 Gbps becomes more common, you'd probably have to revert to all 4 pairs to get it to work.

junitas
@104.2.189.x

junitas to shdesigns

Anon

to shdesigns
@shdesigns: Thanks for the response. So, then pairs 3 and 4 are just noise reduction? The faster speed (1000mpbs) is just achieved by optimizing the data transfer on pairs 1 and 2? Why wouldn't there be (or isn't there) any kind of middle ground using 3 pairs? I'm just interested in finding out why there isn't any kind of middle ground between 100 and 1000.

@Kilroy: yeah, I've got lots of wiring diagrams and I've done this a number of times before. The question is the logic and operational details behind the wiring... what do pairs 3 and 4 do, and why doesn't 3 pairs have an impact on throughput.

Best,
Junitas

shdesigns
Powered By Infinite Improbabilty Drive
Premium Member
join:2000-12-01
Stone Mountain, GA
(Software) pfSense
ARRIS SB6121

shdesigns

Premium Member

Yes, pairs 3/4 are usually capacitively grounded. They provide shielding and help maintain the proper impedance.

As for a middle.sped Ethernt has gone from 10mbit to 100, 1gbit, 10gbit and 100gbit; always by a factor of 10.

3-pair would not make sense. as transmit/receive was divided into pairs, one in each direction.

janderso1
Jim
MVM
join:2000-04-15
Saint Petersburg, FL

1 recommendation

janderso1 to junitas

MVM

to junitas
Have you considered cordless phones and using all four pairs for Gigabit?

Junitas
@104.2.189.x

Junitas

Anon

said by janderso1:

Have you considered cordless phones and using all four pairs for Gigabit?

I already have a cordless phone system, and unfortunately it doesn't really solve this problem.

I have Uverse triple play (phone, cable, internet), which comes in at the back corner of my house where all my Cat6 leads terminate (oddly... outside on a wall). I have to run the original signal (Uverse) into the house, decode it (router/gateway), and then send the whole thing back out to the switch where the cat6 terminates (outside). The issue is that, because I only have one cat6 cable to any location in the house (6 total), I don't have a way to bring it in and send it back AND have the cables wired using all four pairs. I have to split at least one drop, and the real rub is that because that drop is my main drop (to the gateway/router) it's going to cut my outside line to 100mbps.

I can still have a 1gbps LAN, I just can't support 1gbps fiber or internet (Google, Gigapower, etc) without pulling another wire wherever I have the router/gateway (which is doubly hard because I don't have access to my attic/crawlspace (oh, yeah, previous owner sealed the attic space... %@$%@%!).

Anyway, great responses and insights, thanks everybody.
Tikker_LoS
join:2004-04-29
Regina, SK

Tikker_LoS to junitas

Member

to junitas
this might be more work than it's worth then, but depending on how things are wired.....

just run another line inside to where the modem can sit

that way you don't "ruin" the cat5/6 back outside to the rest of the cables

Junitas
@104.2.189.x

Junitas

Anon

said by Tikker_LoS:

this might be more work than it's worth then, but depending on how things are wired.....

just run another line inside to where the modem can sit

that way you don't "ruin" the cat5/6 back outside to the rest of the cables

Yeah, that's kind of the nuclear option that I'm trying to avoid... my wiring runs up into the attic and then back down into the walls (including outside), and having done it before (god help me) I'm worried that pulling two new wires to any location (I'd have to sacrifice and replace an existing line) will inevitably be a messy and painful operation.

The ATT guy did a getto version of this when he did the install, leading a new line along the outside wall and drilling into the house... grrr, I wasn't here when it happened, really hate the wires running along the back siding of my house, trying to get away from having to maintain that option.

However, I may simply have no choice but to run a new line if I want to maintain Cat6... or assume that my entire future will be dependent on 802.11ac or something like that (negating the need for any return from the wifi router).

Thanks,
Junitas
keno5net
join:2002-01-05
Milwaukee, WI

keno5net to junitas

Member

to junitas
Not sure how you use the phone but is a wireless phone system an option? you could put the base station almost anywhere and spread handsets to the locations where they are needed. This would be pricier than running more cable but probably less work. I prefer wireless phones to wireless Ethernet.

Junitas
@104.2.189.x

Junitas

Anon


Per my other post (see above), it doesn't really solve the problem... regardless of where I put the phone I still have to decode the Uverse (or provider) signal somewhere, and that has to be inside.

All my wiring terminates outside, meaning that one wire to any location has to be the base signal (from the demarc to the gateway). If that line is Cat6 I don't have a way to return it to the network (since I only have the one line). I can split that line, but then I'll just be running 10/100 from the point of entry, meaning while my network could theoretically be cat6 (if I keep everything inside the LAN properly wired), I'll still never get 1000mbps internet speeds.

The moral of this story is that anyone who just runs a single Cat6 - who absorbs the cost of doing that install and then balks at paying a little more to run a second line to every location while the walls are open - is a %#$%ing idiot. So frustrating...

junitas

loginforgot
@98.228.241.x

loginforgot to junitas

Anon

to junitas
Perhaps using a single pair extender (Ethernet to VDSL adapter) would work better/more reliably. I have used this box many times with great results...
»www.amazon.com/StarTech- ··· 02CLKFTG

Another option if a coax cable is going where you need is to use MoCA adapters.

robbin
Mod
join:2000-09-21
Leander, TX

robbin to junitas

Mod

to junitas
Can you run a new line between any two current inside locations you now have? For instance, if you could add a new line between the living room and den (use any appropriate rooms in your house) which are already currently wired then that would solve your problem. Basically, using my example, bring the Uverse line into the den using all 4 wires. Connect the Uverse modem LAN to the wire you ran from the den to living room where you install a switch. Existing living room wire takes the signal back outside to current switch where it can distribute throughout maintaining 1000mbps.