JK Audio AutoHybrid - Manual (Page 10)

AutoHybrid Auto-Answer Hybrid
6
Using Your AutoHybrid
Null Adjust
The <Null> is a 15 turn pot used to
determine how much of your <Send>
audio is delivered to the <Caller>
output jack. Use a small flatblade
screwdriver to make adjustments to
this control.
To find the absolute null for any
telephone line, follow this procedure:
1. Place a call to a quiet location.
2. Send a signal into the AutoHybrid
<Send> jack at a moderate level. A
test signal or tone works best.
3. Connect the <Caller> output jack
to a meter or scope, or listen to this
signal through your external audio
equipment.
4. Try to remember the position of the
adjustment screwdriver blade and
the number of turns you are making
as you first adjust clockwise, then
back to the original position, then
counter clockwise.
When the level of this signal is at a
minimum, you have achieved the
maximum null for the phone line. The
maximum null you can achieve is
approximately 20 dB.
Note: The AutoHybrid null is adjusted
at the factory to provide the maximum
amount of null for typical phone lines. In
most instances the null does not have to
be adjusted.