The phone tap is one of the more common types of surveillance activities. The military, government agencies, and police use phone taps to listen to conversations. Additionally, there are private investigators and amateur spies who each use some sort of phone tap to obtain information. It is even possible for regular people to participate in phone tapping, if they have the right equipment. This can be helpful in amassing evidence in divorce cases that my include allegations of infidelity or in instances of feeling threatened by someone else.

In order to set up an effective phone tap, however, it is important to know what types of taps there are, as well as what each kind of phone tap does. You should carefully consider your situation and your budget, and then choose the type of phone surveillance that works best for you.

Soft. This type of phone tap is becoming more and more prevalent as technology advances. This is because a soft tap uses special listening software. The idea is to tap into the phone system of a company or a home. Even tapping into the software at the phone company (even many land lines are now serviced at the phone company by digital lines) can be done. By modifying the software that acts as the 'switchboard and eavesdropper can obtain access to conversations. It is fairly easy to find this sort of phone tap, as long as you have unrestricted access to the system that is affected by the tap.

Hard. The hard phone tap is one where there is actual physical contact with a wire. For instance, a secondary wire is attached to a PBX cable or to a transfer box containing the desired line. A third location receives the signal via a bridge. There is no way for the parties on the line to detect any interference, and it is very difficult to use a bug sweeper to detect a hard phone tap.

Transmit. A transmit phone tap is one that sends information using airwaves. This means that there is no hooking into a line and there is no need to hack into a software system. However, a transmitter gives off a great deal of RF energy. Nearly any person can use a bug sweeper to detect this type of phone tap.