SECTION 6: CONDUCTING A SWEEP
REI OSC-5000E 104
TESTING TELEPHONES WITH OSCOR
The OSCOR’s primary function was not to be a telephone analyzer. However, it does
have some basic telephone analysis capabilities that are not present in most telephone
analyzers.
Test ing for Ho t P hon es o r Hook-Switch By-Pass Bugs
The Balanced Audio Coupler provides a balanced and isolated connection for testing
telephone, fax, or data lines, or unknown wiring or cables. This coupler and patch cord
are used with the OSCOR’s built-in audio amplifier to extract line audio. They can also
be used for direct correlator reference as used in testing for telecom “hot mikes,” hook-
switch bypass, infinity bugs, and electronic triggers. Any suspicious wiring can also be
tested for microphones by monitoring through the system’s reference circuit and listening
to the headphones.
To use the OSCOR to test for audio content on any pair of conductors:
1. Connect the Balanced Audio Coupler (BAC-5000) to the audio patch cord.
2. Plug the other end of the audio patch cord into the EXT REF jack in the audio
panel.
3. Press the EXT button in the AUDIO panel.
4. Press the F1 button (labeled MONITOR/RECEIVER) until the display label reads
MONITOR/REFERENCE.
5. Connect the alligator clips on the Balanced Audio Coupler (BAC-5000) to the
desired pair of conductors.
NOTE: For phone lines, all combinations of the conductors should be tested. REI
provides a coupling device (Modular Phone Adapter) that provides access to all
lines in modular phone connectors that contain 2 to 8 conductors.
6. Adjust the volume control on the OSCOR unit.
With the phone on the hook, there should be no audio on the conductors at all, unless
the phone system is digital. In this case, the phone may have digital signals that will
sound very much like noise on the line. You can unplug the phone from the wall outlet to
verify that digital sound disappears when the phone is unplugged. With the phone
plugged back into the wall and on the hook, tap lightly on the phone with a pencil. If
any audio content is heard, this implies that the phone contains a hook-switch bypass,
hot-speaker (for speakerphones), hot-earpiece, or hot-mike (hot means that the device is
active when the phone is hung up) within the phone. There are some types of phones that
are active even with the phone hung up (many speakerphone models have this problem).
This type of phone is a natural threat and should be replaced.
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