Product Info

Bluetooth Serial Module

AT Command Set

Date : 3 Feb 03 Issue No : 1.9 Doc No : XRBLU020-001SW-0 Page 19 of 38

3. Unsolicited Responses

The ‘AT’ Protocol is a command/response type of protocol. This means that the TDK Serial Module will

normally only respond to AT commands.

Under special circumstances, unsolicited responses will be sent to the host. They are described in the

following subsections.

3.1 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 hex number which

corresponds to the remote device’s Bluetooth address. This response is sent to the host every 2 seconds

until the host either accepts the connection using the ATA command or rejects it using the ATH command.

3.2 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.

3.3 AUDIO ON

This response is sent to the host when a SCO channel has been established.

3.4 AUDIO OFF

This response is sent to the host when an existing SCO channel has been closed.

3.5 AUDIO FAIL

This response is sent to the host when a SCO channel setup fails.

3.6 ERROR 27

This response is sent to the host on power up if the firmware is unlicensed.

3.7 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 will be 2.

The parameter <bd_addr> is the address of the peer device if available.