Abstract: A mobile data terminal which is located proximate to a cellular telephone unit is used to provide customer location information from a foreign cellular telephone service region to the cellular telephone service region in which the customer is a cellular telephone service subscriber. The mobile data terminal provides identification data to a mobile data base radio station located in the foreign cellular telephone service region. The cellular telephone network control center of the cellular telephone service region in which the customer is a subscriber is informed of the foreign cellular telephone service region in which the customer is currently located, possibly through the use of a national clearing house. In this manner, the customer can be reached on the cellular telephone unit in the foreign cellular telephone service region.