If any of the following warning signs apply and you are concerned about phone tapping, covert eavesdropping or wiretapping then it would be wise to arrange a Technical Surveillance Counter Measures ("TSCM") inspection as soon as possible.

DO NOT CALL FROM A SUSPECT TELEPHONE, CELLULAR TELEPHONE OR CORDLESS PHONE.

Consider the acquisition of a phone, fax and data encryption device.

Are you a phone tapping target? If eavesdropping on anything you say, write, or do has the potential to increase someone else's wealth or influence, then the answer must be "yes", you are a potential target.

1. Others know your confidential business or professional trade secrets.
This is the most obvious indicator of covert eavesdropping activities. Theft of confidential information is a multi-billion dollar underground industry in the United States. Often the loss of your secrets will show up in very subtle ways so you should always trust your instincts in this matter. When your competitors know things that are obviously private, or the media finds out about things they should not know, then it is reasonable to suspect phone tapping, technical eavesdropping or bugging.

2. Secret meetings and bids seem to be less than secret.
Confidential meetings and bids are very popular targets for corporate spies. How would you like the plans for the corporate takeovers you're planning to become public knowledge? Would copies of your product designs be of any use to your competitors? Would it be beneficial for your competitors to know how much you're quoting for the same project?

3. People seem to know your activities when they shouldn't.

4. You have noticed strange sounds or volume changes on your phone lines.
This is commonly caused by an amateur eavesdropper when they attach a wiretap, or activate some other phone tapping device. Surveillance devices often cause slight anomalies on the telephone line such a volume shift or drop-out. Professional eavesdroppers and their equipment usually do not make such noises; so if this is going on it could indicate that an amateur eavesdropper is listening in.

5. You have noticed static, popping, or scratching on your phone lines.
This is caused by the capacitive discharge which occurs when two conductors are connected together (such as a bug or wiretap on a phone line). This is also a sign that an amateur eavesdropper or poorly trained spy is playing with your phone lines. It could be nothing more than a problem with your phone line or instrument, but if in doubt you should arrange a TSCM inspection.

6. Sounds are coming from your phone handset when it's hung up.
This is often caused by a hook switch bypass, which turns the telephone receiver into an eavesdropping microphone (and also a speaker). If this is happening then it is likely that there is somebody listening to everything you say or do within twenty feet of the telephone.

7. Your phone often rings and nobody is there, or a very faint tone, or high pitched squeal/beep is heard for a fraction of a second.
This is an indicator of a slave device, or line extender being used on your phone line. This is also a key indicator of a harmonica bug, or infinity transmitter being used. Of course it may also be nothing more then a fax machine or modem calling the wrong number.

8. You can hear a tone on your line when your phone is on the hook (by using an external amplifier).
To check for something like this you would have to obtain a "recorder starter" interface (with a VOX option), or some kind of a high gain audio amplifier such as a uAmp or Kaiser 1059. Then with the phone hung-up listen to your telephone wiring. If you hear a faint, solid, dual tone it is a dead giveaway of someone using a "slave" eavesdropping device on your (or one of your neighbors) telephone lines. Such devices create a "command tone" when the subject hangs up the phone (so you must ensure that all of your phones are hung-up).