It is a very disconcerting feeling when you think someone is spying on your phone conversations -- a spy could overhear personal conversations, credit card information and various pieces information that can be used against you. If you suspect someone is spying on your phone conversations and has tapped your land line or cell phone, there are certain telltale signs to look for to help you discover a phone tap.
Make yourself aware of the information other people know about you. If other people appear to be aware of information meant to stay private, such as business deals or trade secrets, you could be the victim of phone tapping. When other people know about business dealings revealed only over the telephone, this should be your first sign that something is amiss.
Listen to the background noise of all outgoing calls. If there are strange background noises you hear when you pick up the receiver or when you place a call, this is a good sign the phone line is being tapped.
Monitor the volume levels. When a phone is being tapped, the volume levels can be erratic -- suddenly going from high to low volume or vice versa. Pay attention to any changes such as this when you are placing calls.
Walk near a television, radio or other electronic device when placing a call. Some tapping devices will cause interference with nearby electric appliances. The result could be the sound in your TV or other appliances becoming distorted or putting out static noise.
Pay attention to any suspicious activity such as a break-in to your home in which nothing is stolen. In order to tap a phone, spies will have to install a device directly inside the phone and thus must enter your home or have access to your cell phone. Make note of any oddly opened doors or windows, or indications that someone else has been in your home.