The three basic types of scanning equipment that allow a user to listen to local communication channels are handheld, mobile and desktop scanners. These electronic devices are also referred to as police scanners.
Scanners are capable of receiving transmissions over the air waves by scanning multiple frequencies. These channels are commonly used by federal or state agencies, businesses, medical facilities, emergency medical services or taxi dispatchers within a community.
Based on the type of radio signals that scanners can pick up, these devices can also be classified into four kinds: analog, trunking, phase 1 digital and phase 2 digital scanners. Analog scanners are commonly used to listen to local communications within a small city or in the countryside. The use of accessory equipment, such as additional antennas and computer software, vastly improves and enhances the scanning experience.