Roaming is the ability for a wireless mobile customer to automatically make and receive voice calls, send and receive data, or access other services, including home data services, when travelling outside the geographical coverage area of the home network. Typically the cost of roaming is considerably higher than the regular cost within the home network. There are two types of charges when using a wireless mobile service: Airtime and Long distance. While Airtime is always charge. Long distance charges vary depending of several factors.