Telephone Transmitters

Telephone transmitters

Telephone transmitters are devices connected to a target's telephone line that listens to telephone conversations and transmit those conversations to a hidden or standing recording device. Such devices as telephone transmitters are identified as two basic types or models;

the first and most commonly known type is the series connected transmitter.

The second type of telephone transmitter is known as the parallel connected telephone transmitter.

A series connected telephone transmitter is connected at a point in the telephone line where the line is cut and the device is connected between the two cut ends. A series telephone transmitter transmit only the conversation that takes place on that line. If the target has numerous lines than one must connect to each line individually with a series telephone transmitter. If the targets telephone system is multiple lines than we must use a demultiplexer or we must install individual transmitter on line by line.

A parallel connected telephone transmitter is connected at two points on the telephone line, the transmitter must be connected to each wire of the telephone line pair. When the telephone is used the conversation is transmitted to a hidden recorder or a known recording device.

In order to install any telephone transmitter the telephone and its line must be disconnected even if its a few seconds or momentarily. An installation of a telephone transmitter can be installed in the junction box of telephone wires or anywhere along the line.

When installing care must be taken to avoid cutting a line that is used by an intruder alarm system. Cutting this line may sound an alarm to the local police department. Cutting such a line could also set off a sensitive detector in your alarm system.

Most telephone transmitters are parasitic that means that the transmitter uses telephone line energy. Parallel connected telephone transmitters are most often connected with electronic clips such connections require minor stripping of the line insulation. There are series and parallel connected telephone transmitters that have their own batteries as back ups to avoid showing a voltage drop on the existing telephone lines.

Those connected telephone transmitters that use line voltage to transmit are also known as leeches or parasitic devices. The transmission distance of connected telephone transmitters depends on the small current off the line and the device using the telephone line as a long wire aerial antenna. Usually such distance of transmission is about 22 to 52 meters but there are devices that transmit about 500 to 1000 meters in distance.

In the telephone transmitter market you find small plastic shield waterproof transmitters which may be connected to the telephone line or up in the telephone pole wire box.

Inside a building, a transmitter may be connected to the

telephone line or hidden inside a telephone handset.

A drop-in telephone transmitter like those seen in spy films are designed to be installed by replacing the telephone microphone (mouthpiece) cartridge. The telephone microphone of the target is removed and the transmitting unit is installed. Most so called drop in microphones must attached to the microphone points of contact or terminals. The words “drop in” is not correct it takes time. Time is not safe you can be caught installing the unit.

In the next few days I will post design drawings of series and parallel transmitters.

Remember if you need to have your office or building swept for occult telephone transmitters or other surveillance equipment contact me through this blog. I will answer you as soon as possible. Remember, I do contracts outside the country.