Can telephones and networking share the same Category 5 cable?

Question

I know that technically the answer is yes if you do not follow standards. The telephones use two of the 8 wires and the internet uses only 4. The question is would the two services cause too much signal degregation in the wire?

Answer 1

Apart from any cross-talk, this is only good for 2 wire phones, if you ever need to use a system phone many of these require 4 wire. What you should do is run 2 cables to each point, then you can use both independently, and this takes the same time to install as running 1.

Answer 2

It depends.

If the network runs at no more than 100 Mbps you can. If you run at 1000 Mbps (1 Gbps) you cannot.

At the lower speed, you use 2 of the 4 pairs for data. These are connected to pins 1,2,3, and 6. Usually Orange white is 1, orange 2, green white 3, green 6. You do not use pins 4,5,7, and 8 (usually the colors are blue, blue white, brown white, and brown respectively). You can remove the pins 4, 5, 7, and 8 from data and use these for 2 phone lines if you wish.

If you are using RJ 45 connectors for phone, phone line # 1 goes on pins 4 & 5; phone line # 2 goes on pins3 and 6.