Manual button - This lets the user manually step through a range of frequencies stored in the scanner. Modern scanners have 100 to 300 channels for storing frequencies in the built-in memory. More expensive models have even more.

Scan button - This starts the scanner on a continuous loop through all of the frequency banks (containing stored frequencies). The scanner stops when it detects a radio signal on a stored frequency; it moves to the next stored frequency when the radio signal ends. The user can typically enable or disable certain banks of frequencies for scanning. Each bank can hold 10 to 30 frequencies, depending on the brand and model of the radio scanner. Often, banks contain frequencies according to the type of radio service. Types include emergency, police, fire, aviation, marine, and business.

Delay button - This makes the scanner stall for a short duration on a frequency before moving to the next one. This delay helps the user hear the other part of the radio conversation on that frequency.

Lockout button - This temporarily disables the radio scanner from stopping on a stored frequency. For example, you might want to lockout the frequency of a busy airport tower at peak travel time during the day when you're really trying to hear the traffic helicopters in your area.
Radio scanners usually come with small whip antennas as well as an external antenna connector. An outside antenna or attic antenna enables you to hear more transmissions at a greater distance.

Scanners cannot hear everything. The typical consumer-grade scanner cannot listen in on 900-MHz cordless phones that use digital spread spectrum (DSS) technology. Analogue cell phone frequencies are also blocked by law on all scanners.