User's Manual

Class 1 Bluetooth v2.0 Module
User’s Guide
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CONN-GUIDE-BT730_v0.9
6.4 Unsolicited Responses
The ‘AT’ Protocol is a command/response type of protocol. This means that the Laird device will normally
only respond to AT commands.
Under special circumstances, unsolicited responses are sent to the host. They are described in the
following subsections.
6.4.1 RING
This string is sent to the host when a remote device is initiating a serial port connection. The fully qualified
string is in the form RING 012345678901 where 012345678901 is a 12 digit hexadecimal number which
corresponds to the remote device’s Bluetooth address. This response is sent to the host every two
seconds until the host either accepts the connection using the ATA command or rejects it using the ATH
command.
6.4.2 PIN?
This response is sent to the host during a pairing negotiation.
The fully qualified string is PIN? 012345678901 where 012345678901 is the Bluetooth address of the
peer device. In response, the host must supply a pin code which is entered using the AT+BTK command.
If the peer address does not supply the address in the message exchange, then the address is specified
as 000000000000 – and the paring will proceed as normal.
6.4.3 AUDIO ON
This response is sent to the host when a SCO channel has been established.
6.4.4 AUDIO OFF
This response is sent to the host when an existing SCO channel has been closed.
6.4.5 AUDIO FAIL
This response is sent to the host when a SCO channel setup fails.
6.4.6 ERROR 27
This response is sent to the host on power up if the firmware is unlicensed.
6.4.7 PAIR n <bd_addr>
This response is sent to the host on termination of a pairing process. If pairing was successful then ‘n’ = 0,
if a timeout occurred then ‘n’=1 and for all other unsuccessful outcomes the value is 2.
The parameter <bd_addr> is the address of the peer device if available.
6.4.8 PAIR 0 <bd_addr> MM
This response is sent to the host on termination of a successful pairing process. The optional MM is sent
only if S Register 538 is set to 1 to automatically save the link key. The value MM indicates the result of
the save operation and a value of 00 implies success, otherwise the value corresponds to an error code.