3. Your phone makes noise on its own. If you hear noises coming from your phone even when you're not using it, it may have been turned into an eavesdropping microphone and speaker. This is achieved with a hookswitch bypass and means that someone can probably hear everything you say or do within 20 feet of the phone. Additionally, a dial tone while your phone is on the hook is a sign of a slave eavesdropping device. This can be verified using an external amplifier.

4. Your radio has strange interference. Some eavesdropping devices use frequencies that are close to the FM radio band. To find out if your line is tapped with one of these gadgets, you can set your radio to mono, tune in to the far end of the band and listen for squeals, moving around the room if necessary. You should also listen for anomalies in your car radio, because antennas are often used by eavesdroppers.

5. Your environment just seems different. A wiretapper who has gained access to your home or office may move furniture in order to gain access to lines. If something seems strange — for instance, the couch has moved slightly or rug imprints are different — your line just might be tapped.

6. Your outside phone box has extra hardware. Sometimes, a physical check is required to notice a wiretap. Take a look at the outside of your phone box and look for anything unusual, such as hardware that seems like it was hastily installed. You should be sure to check the "restricted" side of the box, which will require a special Allen wrench.

7. You find a recording machine. Don't assume that everything on your phone is there because your provider put it there. If you've found a recording device or something else that looks suspicious, check it out. Follow your wires to make sure that they're clean.

8. You're being blackmailed. Not every wiretapper is discreet. In fact, some may specifically tell you that they've wiretapped you and attempt to extort money from you in exchange for their silence.

9. Your receiver has extra hardware. Obviously, if you notice a microphone stuck on your receiver, you should be suspicious. Beyond that, open up your phone receiver to see if there's anything that doesn't belong, such as an induction-coil microphone.

10. You notice a lot of utility trucks near the premises. If you see the same vehicles or utility trucks quite often but don't ever see people getting in or out of them, someone may be listening in on your calls. The snoopers will be 500 to 700 feet away, and their vehicles will have tinted windows.

11. Your TV has interference. Eavesdropping signals can interfere with TV broadcast frequencies, specifically UHF channels. You can even use a handheld TV with an antenna to sweep a room for interference.

12. You are the victim of a burglary, but nothing was stolen. That person who broke into your home or office may not have been after your precious possessions, but rather your conversations. If you've become the victim of a fake burglary, it would be wise to double-check your lines.

13. Your wall plates are moved. A wiretapper may use your phone's wall connection to gain access to your line. Look for signs that this hardware is a different color or crooked, and definitely take a closer look if you notice debris on the floor or screws that have been moved.

14. You've had a mysterious repair. Some wiretappers will gain access to your line under the guise of a repair. If a utility-company employee shows up when you haven't specifically requested one, there's a good reason to be suspicious. Call to verify the repairman's visit with your provider or watch his actions carefully.

15. There are no signs. If you don't notice any of the aforementioned signs, your line could be wiretapped anyway. Most amateur spies will exhibit at least one the telltale signs outlined above, but government tapping is executed at the local exchange-carrier-switching center of your phone company, so there are no strange sounds to hear or hardware to find. If you truly want to have a private conversation, do it face-to-face.

16. Your phone company doesn't help. If you've asked your phone company to look for wiretaps but it never finds anything, it could be administering a government request.

17. You use a cordless phone. Cordless phones are extremely easy to listen in on and can be picked up by a number of devices on the same frequency. If you're using a cordless phone, you should just assume that your conversation can be heard by anyone who wants to listen.

Chances are, if you're being wiretapped — especially by an amateur — you're going to know that something's going on. From fairly obvious interference problems to strange utility-worker behavior, the signs are easy to pick up on if you're looking. However, wiretapping, especially on VoIP lines, can be executed by professionals without telltale hardware. In fact, plenty of snooping can be done at the software level, which is virtually undetectable. In the end, your best bet is to discuss sensitive matters in person.