DETAILED CPM-700 PROCEDURE
29
REI
CPM-700
AUDIO TESTING
The CPM’s Auxiliary Input amplifier is used with the supplied Auxiliary Patch
Cable to “listen” to suspicious wiring for the presence of voices or other
signals. The balanced input allows testing of phones and phone lines for
modifications, and after-hour evidence monitoring.
NOTE: Monitoring of phone lines is for temporary testing purposes only
and is not to be used for surreptitious interception.
*WARNING: The Aux Input is not to be connected to power lines or circuits
with voltages over 52 volts. Unit damage or shock hazard may result!
NOTE: The CPM audio amplifier is sufficient for low-
level threats. For more sophisticated audio testing, the
CMA-100 from REI provides additional amplification,
voltmeter, voice band filters, and the ability to bias the
line with voltage for additional testing.
Unit Set-up for Audio Testing
Remove any probe connected to the front panel Probe Input and plug the
Auxiliary input Patch Cord into the side Aux Input.
NOTE: The Auxiliary Input will not function if a probe is connected to the
Probe input.
NOTE: The CPM-700 utilizes an AGC (Automatic Gain Control) in the
audio circuitry to control the volume and prevent overloads. The bar graph
display will not be active beyond two or three segments when using the
Audio Patch Cord.
Phone Line Audio Test
Test telephones and lines for devices such as infinity or harmonic bugs that
listen to the room while on-hook.
1.
Identify the ring and tip conductors of the phone line (usually red &
green) and connect the Auxiliary Input Patch Cord to these points.
2.
Listen through the Headphones for the Known Sound Source (a
normal unmodified telephone will not pass audio when “on
hook”.) If an “electronic trigger” is in use or a hook-switch bypass