BASIC OPERATIONS
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The main features of the camcorder's transmission channel can be detected:
signals in the frequency range of the "reverse channel" (5 - 40 MHz);
the frequency of the detected signal does not match any of the broadcast television
channels;
signal change (on an oscilloscope) with a sharp change in the illumination in the room.
7.3. BASIC OPERATION #3
DETECTION OF NONLINEARITY IN THE CABLE
Purpose of basic operation
- detection of the devices, which are connected to the cable.
Objects to test:
telephone cables;
LAN cables;
coaxial TV cables;
other low-current cables.
The used device - NLJD
Additional equipment
- RJ45 short-circuit socket
(Fig.1, item 15)
.
7.3.1. IMPLEMENTATION OF BASIC OPERATION #3
ANALOG TELEPHONE LINE TESTING
Most eavesdropping devices are connecting to the telephone cable line in parallel (telephone
transmitters, voice recorders, high frequency wire transmitters, cable microphones). Sometimes,
telephone transmitters are connecting to a "break" in one of the wires of the telephone cable.
Based on this, testing must be carried out in two modes:
the other end of the cable is open (for detecting parallel connections);
the other end of the cable is short-circuited (for detecting serial connections).
For short circuit of the cable equipped with RJ plug special RJ45 socket is used
(Fig.1, item 15)
.
Initial status
The object of testing is a four-wire PBX analog telephone cable. The cable has two central
wires. Telephone set is connected to the cable through a telephone jack. The handset is off-hook.
The cable is powered by the PBX and operates normally. The cable is equipped with a 6P4C plug
(all four wires are connected).
Analog type telephone line testing algorithm:
1. Disconnect the telephone cable from the PBX (the cable is not short-circuited)
2. Disconnect the telephone set from the cable.
3. Connect ST 301 to the cable (options
.
4. Turn on ST 301, NLJD.
