User guide

1. Introduction
This document describes the protocol used to control and configure the following Ezurio Bluetooth
devices:
• EZURiO Bluetooth Intelligent Serial Module (BISM and BISM2)
• EZURiO Embedded Bluetooth Module (AT Interface)
• EZURiO PCMCIA Adaptor
• EZURiO RS-232 Adaptor
• EZURiO Universal RS-232 Adaptor
• go blue Activator
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. The telephony commands have been extended to make the EZURiO device perform the
two core actions of a Bluetooth device, which is make/break a connection and Inquiry. Many other
AT commands are also provided to perform ancillary functions, such as, pairing, trusted device
database management and S Register maintenance.
Just like telephony modems, the EZURiO device powers up in an unconnected state and will only
respond via the serial interface. In this state the EZURiO 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 command set is extensive enough to allow a host to make
connections which are authenticated and/or encrypted or not authenticated and/or encrypted or
any combination of these. Commands 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 configured for baud rates from 1200 up to 921600,
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.
DSH_50003_v1v3 AT Command Reference 4 of 33