2 channel scan is the most widely used scanning program. A two channel scan is when an enterprise uses radios with specific work groups. Channel one can be assigned to production, while channel two goes to maintenance. Channel three is for shipping. Although it is impossible to hear all the departments conversing, it is possible to communicate with everyone on occasion. Every radio sets up to check for activity on the channel it is assigned and another channel (known collectively as the all-call channel). Here, the radios of production workers are looking for activity on both channel 1 and all channel 1. Radios used by maintenance workers scan for activity on channels three and all call.