User's Manual
9
www.lairdtech.com
Laird Technologies
BTM510/511
Bluetooth
®
Multimedia Module
INTRODUCTION
This document describes the protocol used to control and congure the BTM Bluetooth device.
The protocol is similar to the industry standard Hayes AT protocol used in telephony modems which is
appropriate for cable replacement scenarios, as both types of devices are connection oriented.
Just like telephony modems, Laird Technologies’ devices power up in an unconnected state and will only
respond via the serial interface. In this state, the device will not even respond to Bluetooth inquiries. Then,
just like controlling a modem, the host can issue AT commands which map to various Bluetooth activities.
The conguration of the device can be saved, so that on a subsequent power up the device is discoverable
or automatically connects.
The device has a serial interface which can be congured for baud rates from 1200 up to 921600 (default
setting is 9600) and an RF communications end point. The latter has a concept of connected and unconnected
modes and the former will have a concept of command and data modes. This leads to the matrix of states
shown below.
RF Unconnected RF Connected
Local Command Mode OK OK
Remote Command Mode ILLEGAL OK
Data Mode ILLEGAL OK
The combinations ‘Data and RF Unconnected Mode’ and ‘Remote Command and RF Unconnected Mode’
do not make sense and will be ignored.
Navigation between these states is done using the AT commands which are described in detail in
subsequent sections.
AT COMMAND SET
REFERENCE