Introduction: Direct Connecting Two (old Fashioned) Modems or Telephones.

By Computothought
About: computoman.blogspot.com Bytesize articles instead of a trilogy in one post.

Ever wanted to reuse those old telephones and or modems using just two wires. This instructable shows you several options. Get a continuity tester to make your job easier.

Step 1: Circuit 1.

This first circuit if you just want to use a battery.  For short distances use the nine volt battery for compactness.

Step 2: Circuit 2.

This circuit is for using a wallwart. Better for a more permanent setup. Originally I intended to use coax but any 2 line wire will do.

Step 3: Circuit 3.

This is for a more permenant circiut and with buzzer. As soon as you pick up the phone the buzzer should sound. Thanx to Markus Wandel.

Step 4: Cabling.

Coax: hard to connect to, but cheap. We were going to use the in wall cabling for the tv, but I want to make sure nothing is connected. Did disconnect the outside connection up in the attic. I will check it again before using it.

Telephone cable: Cheap and easy to connect to. either the two or the four line will work as long as you use the corresponding lines.

Cat 5 cable. Do not recommend using cat five cable unless the rj45 cable ends are not connected. There can be real problems. Newer 1g networks use all eight lines so you would not be able to use the cable anyway. Secondly there is risk of damage to equipment and safety issues if you connect eight wire devices (i.e cable tester) to the network. Direct connecting two computers requires a crossover cable. Wiring for crossover cables varies, so you really have to know what you are doing. Get a qualifid professional to help you if you are the least bit unsure of what to do. Lines seven and eight sometimes are best to use but not always. Check your cabling for sure.  Get a head set.  Instead, I would recommend using telephony software that does not require a commercial host. Then you do not even need the telephone.

Note: this frame was wiped out during editing so I had to redo it from memory. The one time I did not save the page, I knew it would happen.

Step 5:

If you are going to use cat 5 network cable. I strongly recommend making a breakout jig. Of course I would recommend that for any cabling project.