"Andy Evans" wrote in
message


I want high quality sound from the telephone for making
long distance coaching calls. So I want to use a binaural
headset and microphone. I could get a seperate headset
like the Plantronics ones, but it seems to me that I
could just link the telephone to my Mac computer and
listen and record (I'd like to record too) etc from the
computer, using the headset and microphone I use for
Skype already.

Do I need an interface, or is the line in and line out to
the telephone just normal 2 volts type line level?

Telephone lines are special. They are typically balanced, ungrounded, and
still called on to pass ringing signals that are like 50-90 volts AC with
significant current behind them.

In other words I could make a DIY interconnect with just
phono plugs for the computer line in/
line out sockets?

Look up telephone interface schematics on the web. You'll typically find a
matching/isolating/balancing transformer and some kind of peak voltage
limiter.

http://www.epanorama.net/circuits/teleinterface.html