NTT DoCoMo launched Freedom Of Mobile multimedia Access (FOMA) on a full scale in 2001, and it has been expanding its service area ever since then. However, it will take a long time to expand and catch up with the Personal Digital Cellular (PDC) service area. In the meantime, NTT DoCoMo will provide the Dual Network Service in light of user convenience. This article describes the Dual Network Service and provides a detailed description of the control method.