Connecting two computers up through phone line in wall?

Is it true that you can use the normal phone line that already exists in your home to connect two computers? How?

Connecting two computers up through phone line in wall?anti virus protection

probably not unless you upgraded to home networking. Generally speaking home phone wiring is a 4 conductor wire. Red, Green, Yellow, Black. You use to wires per line therefore most home could have up to 2 different lines and use the same wire. I'm assuming when you say connect you mean like as a network and not just to share the same line to dial in to the internet. If you have high speed and are connecting to a router or something you will need a 8-conductor Cat-5 wire. It has a wider plug on the end although the connector does look similar to a phone cord plug

Connecting two computers up through phone line in wall?antivirus

This is possible if you have two different phone lines. You stick a modem in each computer. You then configure Windows Networking to allow each computer access to the other
There's probably no technical reason, but certainly a management problem. You'd always have to make sure the line is available when you need it. If it's also the house phone for talking, interruptions from picking up the receiver could corrupt data transmission.

-MM