The data format of GATT will be described next. GATT data has a hierarchical structure as shown in FIG. 9, which includes three elements called a service, a characteristic, and a descriptor. Each of the service, the characteristic, and the descriptor can be identified by a UUID (Universally Unique Identifier) of 32 digits, which is assigned to each element. If one service includes a plurality of characteristics, a single UUID is assigned to each characteristic, and information defined by the BLE standard or information defined by the user is identified. The GATT client designates UUIDs corresponding to the services and the characteristics, thereby executing read/write for a value held on a characteristic basis. Here, the UUID is used as an identifier configured to uniquely identify an object on software. The UUID is a 128-bit numerical value and is normally expressed in hexadecimal as, for example, 550e8400-e29b-41d4-a716-446655440000. Note that some services, characteristics, and descriptors are defined by the standard of Bluetooth Special Interest Group (Bluetooth SIG) or are unique to a vendor. The UUID of an element unique to a vendor is expressed by 32 digits, as described above. On the other hand, the UUID of an element defined by the standard of Bluetooth SIG is expressed by four digits. For example, the UUID of an element defined by the standard of Bluetooth SIG can be expressed as 2A49.
