The most popular scanning application is known as 2 channel scan. Two channel scan supposes that an enterprise is using radios that have specific work groups assigned to specific channels. For example, channel one is assigned to production and channel two is assigned to maintenance and channel three is assigned to shipping. It is not practical to have all departments listening to each other conversations but is important to reach everyone at once on some occasions. Each radio is set to scan for activity on their specific channel and one other channel (known as the all call channel). In our example, production worker radios are scanning for activity on channel one and the all call channel. Maintenance worker radios are scanning for activity on channel three and the all call channel.