Use Cat4 for Ethernet

Question

Is it possible, and if so, what are the cons of using a CAT4 cable as an Ethernet cable?

I'm renting a split level condo with my networking closet downstairs and my office upstairs. I believe in using a wired network connection whenever possible, but this condo isn't new enough to have used CAT5 for the telephone jacks. There doesn't seem to be an obvious, practical solution to run a new CAT5 cable through the walls or vents due to the construction of the condo. Although the "networking closet" is in the furnace room, I can't seem to successfully fish a cable through any ducts. Yes, I have briefly considered Ethernet over powerline, but I just don't think that would be a reliable connection. I might consider trying some kind of ethernet over coax (if such a thing exists). But it seems that the least destructive, most reliable, and most cost effective way to get a connection to that room is to utilize the CAT4 that's not being used and is already in the walls.

I apologize if this is a duplicate or if I'm asking in the wrong community (both reacuring themes during my time using stack exchange)

TIA.

Answer 1

You're not going to hurt anything by giving it a try, right?

The likely outcome is that you will not be able to get reliable performance above a 10Mbps link speed. The devices may try to link up faster than that, but will experience many errors at faster speeds. If you are okay with 10Mbit speeds, force the devices on each end of the circuit to 10/full duplex instead of allowing them to auto negotiate.

In the end, it's likely worth it to hire someone to run cable for you, or give powerline transmission a try. I've used it several times, with good results. Not gigabit, but much better than 10Mbps.

Answer 2

MOCA (Multimedia over COAX) is basically Ethernet over COAX. I've had great success with it, and it's how most cable companies do whole-house DVR and other neat things.

Answer 3

Cat 4 is vanishingly rare. Unless you've seen "Cat 4" (or some variant thereof) printed on the cable jackets of the stuff in your walls, you probably have Cat 3 voice grade wiring.

Cat 3 was good enough for 10 megabit/sec 10BASE-T Ethernet from the 1990's, but only if it was run point-to-point, which is uncommon for most voice grade telephone wiring. Most analog telephone wiring has branches or long busses with multiple jacks per bus, or unused stubs/spurs of wiring beyond the jack you want to use. These topologies do not support the signal integrity needed for even old 10BASE-T.

There are solutions for getting up to a few megabits/sec of networking speed out of spare lines in your home phoneline wiring. HomePNA (the Home Phoneline Networking Alliance) was one group. I think their efforts became part of G.Hn. You might see if there are any products from those groups on the market.

MoCA 2 is a way to do a few hundred megabits per second over coax.

G.Hn and HomePlug AV2 are ways to do a few hundred megabits per second over your power wiring.

To be honest, all the non-Ethernet solutions for home wired networking kinda suck. If pulling real Cat5e or better Ethernet cable is not an option, wireless extension is probably the best-supported way to get network service to other parts of your house.

Answer 4

Why not use the CAT4 cable that's in place already as the fish for the CAT5 you want. De-energize, cut the CAT4 and attach the CAT5.
Pull from the other side and fingers crossed you'll have a new line.