JK Audio THAT-1 - Manual (Page 3)

3
Operation
To Phone Jack
This is a line level input for signals that you want to send
down the phone line. This jack can be connected to an
audio output such as the headphone output jack on a
tape recorder, the line output of a PC audio card, or the
line output from a CD player or audio mixer.
From Phone Jack
This is a variable mic level output from the telephone
line.This jack provides a mix of both sides of the
conversation. In other words, whatever you send down
the phone line will come back on this jack mixed with the
audio from the other side of the call. This is not
adjustable. We picked a suitable mix ratio for most
telephones.
The supplied adapter cable allows you to take the left
channel from a 1/8" mini stereo headphone or mono
microphone jack and attach it to the RCA jack on THAT-1.