I need to run about 100-120 feet of cat5e cable to connect our bedroom
to the utility room where the network switch, DSL router etc is. I
ALSO need to run a phone cable, from utility room to the same
bedroom. I am wondering if all 8 wires on a cat5e cable are used for
Ethernet purposes, and if that is not the case, is there a couple I
could use for phone. That way I could save $$ and time by running one
cable instead of two.
No all 8 wires are not used. An Ethernet patch cable has only 4
conductors - there should be a hint in that.
You mention a router... are you using only one port on the router? Not sure
what your plans are.
The intended topology of our home network is as follows:
-> DSL Jack
-> DSL Modem
-> Network Switch
-> Linux box
-> Windows XP box
-> LinkSys wireless router
-> Laptop 1
-> Laptop 2
DSL modem and network switch are in the basement utility room, and
Windows XP box has been relocated to our bedroom on the opposite side
of the house. That necessitates a 120 ft cable run.
Also RJ45 and RJ12 plugs are physically compatible. That is you can
plug an RJ12 (phone) into an RJ45(Ethernet). And if you use the proper
wiring convention (forget if its 568A or 568B) the center wires will be
open and you can have both phone and ethernet in the same jack. Not
that you would want too.
At my old home I had 1 pair running up to my computer room that brought
my ISDN line, 1 pair returning to the basement which was one of the
house phone line that ran from my ISDN Adapter, and connected to the
rest of the house phone lines, and 2 pair for ethernet that ran back to
basement for my router in the basement. It was perfect.
Just to jump into the middle here...
Gigabit ethernet DOES use ALL eight wires...
Even if you only do 100mb networking, having phone on the unused pair will
still introduce noise and degrade your network.
Pull a separate line for telephone! Do NOT mix your networking with any
other signals on the same bundle.
A phone line on 1 pair will introduce a lot less noise than a network
line on 2 pair. Its negligible. I would mix. Hes not running an ISP
anyway... Of course I am also one of those people that likes to have an
extra pair, so if you can you might as well run 2. 2xcat 5 is preferred
over 1xcat 5 1x phone line.
Cat5 only needs two pairs of wires, but make sure you reserve color pairs.
If you strip back enough of the outer sheath, you'll find that wire pairs
are visible. Each color pair, like blue and white/blue is twisted and this
is important for the cat5 spec.
CAT5e cable is usually used for 100Mbit connections which require only
four wires. However this cable has also been used for 1000Mbit
connections which do require all eight conductors. If you don't plan
on using Gigabit then you should be okay.
No matter what happens, someone will find a way to take it too
That's cool, I have no gigabit plans at the moment. Question of the
day is, then, which wires are used. I understand that I could pick any
wires as long as I connect them to the jack properly. I use Leviton
jacks from Home Depot.
Cat 5 is fine for phone and Cat 5 is fine for Ethernet, but it is bad
practice to mix the two on the same cable. If at any time you have
phone or Ethernet connection problems, you will need to know what
arcane way the system was wired and it can make testing difficult
unless you have good diagrams. The problem becomes more severe as the
complexity of your system grows.
I'm not saying it won't work and it may be the cheapest way to go, but
a Wiring Pro wouldn't do it that way.
[about using a pair of wires in an Ethernet Cat 5 cable for phone]
It would likely work, but at what quality? Even with twisted pairs, there
will be some cross talk between them and the question becomes, "How much
can you tolerate"?
For phone users, this cross talk will show up as hiss and other noise in
the call. Depending on how much is introduced, this may not even be
noticable, or it might be downright annoying.
For data, the cross talk will show up as data errors which will only be
noticable as a slow-down in network traffic (as packets with errors are
"Never ascribe to malice what can equally be explained by incompetence."
On Tue, 07 Jun 2005 13:50:10 GMT, email@example.com
(Calvin Henry-Cotnam) wrote:
We did some real life testing a few years ago at a large company that
sells Business Machines Internationally. It is the ringing current
that spikes the LAN and that is more pronounced if it is an old style
magnetic ringer. We could not detect any problems with the phone.
If you actually had some physical contact the ringing current would
certainly smoke the LAN card.
100base-T uses two of the four pairs. However, if you're thinking of
upgrading to 1000base-T, you'd be out of luck - gigabit ethernet uses all
four pairs and requires cat6.
I'd choose one of two options:
- Go wireless for both the phone (800mhz/2Ghz) and network (with
- Run two separate cables (one being cat6) and be done with it
A lot of times there is more to Ethernet than meets the eye. It's
very easy to mess up the connectors and put the wrong colored wire in
the wrong crimp slot. Often more is needed than just a simple
continuity check. Running the cable too close to electric conduits or
fluourescent lamps can cause problems. The mere act of stretching the
cable with >25 lbs of force during installation can dramatically
degrade the performance permanantly.
That's why they have guys going around with 5-10 thousand dollar Fluke
meters going around certifying that the cable installation as meeting
the performance standards for Cat 5, 5e, or 6. Many businesses
For a home installation, you may not have (or even need) the big bucks
fancy meter, but it pays to take extra care in doing the installation
correctly and not mix it with phone wiring, doorbell circuits, etc.
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