This standard is related to a radio system which uses 4FSK method (4-Level Frequency Shift Keying) among narrow band digital mobile telecommunication methods as a mobile telecommunication system for business use that uses 260MHz band.

Among mobile telecommunication radio systems which use 4-level digital modulation methods specified in the Article 57-3-2, Clause 1-1 of the Ordinance Regulating Radio Equipment, this standard specifies a mobile telecommunication system for business use that uses a novel modulation method (4-Level Frequency Shift Keying: 4FSK), and is a relatively convenient radio system based on voice telecommunication, and the like for a disaster prevention mobile radio system.

The 4FSK/SCPC digital mobile telecommunication system for a local government built as a self-supporting communication network comprises a base station and a mobile station, and the like and communicates between a base station and a mobile station or between mobile stations (via a base station or directly).

The telecommunication method will be SCPC method in which basically one radio channel corresponds to one radio carrier, and one radio carrier enables a communication service to one base station.