Recording phone calls to PC - from scratch

[kozikowski]

Since nobody hit this yet...

The analog telephone line has some interesting properties. The obvious one is the ability to send and receive two independent conversations simultaneously over one pair of wires. If your phone has three wires, that odd one is used for ground or phone instrument lights -- or sometimes four wires for two different telephone numbers. But the show, your voice, always goes down two wires -- Red and Green in the US.

A lesser known characteristic is ringing current. To get your phone to ring, the phone company pushes a very healthy 70 volts AC down the wires and if you happen to be holding the wires at that time, you will get a serious but usually not fatal jolt. This usually only happens once. They send it multiple times, but you won't be there when they do.

The $12 USD way to listen to the conversations on the phone line is to simply jam an amplifier onto the phone line and listen. All the units in that price range do something similar. This is the one that gives you a nuclear voice and your mom at the other end a really, really tiny voice.

Next up are the units that plug in place of your handset instead of the phone line. Those use the electronics in the phone to help separate the two conversations. They're only partially successful because the electronics inside your phone are designed intentionally to leak. It's called sidetone and it's what makes a regular phone so much more comfortable to use than a cell phone which doesn't have sidetone.

The grownups use Telephone Hybrids which do a complete job of separating the two conversations. This is what the call-in talk shows use. You will not buy one of these by accident because they go for $2,000 USD and up.

It is at that instant that outfitting yourself with a VOIP account and capture software makes a lot of sense. The two cheap versions of Pamela don't work.

Koz