This procedure may have to be repeated under certain circumstances. This profile does not support multiple instances of its implementation in the same device. Security is ensured by authenticating the other party upon connection establishment, and by encrypting all user data. The baseband and LMP mechanisms for authentication and encryption are used. Before a DT can use the services of a GW for the first time, the two devices have to initialise.
Initialization includes exchanging a PIN code, creation of link keys and service discovery.
A link has to be established before calls can be initiated or received. This requires paging of the other device. The GW and DT provide serial port emulation. For the serial port emulation, the serial port profile is used. An SCO link is used to transport audio.