2.4GH
Z
B
LUETOOTH
T
RANSCEIVER
M
ODULE
E
VALUATION
K
IT
BRM01
Simple Operation
Connect a headset via the 2.5mm headset jack to each unit.
Insert 3xAAA batteries into the battery holders. Observe correct polarity.
Connect the power connect jumper JP1. The BRM will power-up and the LEDs will cycle through AMBER, AMBER-
GREEN, AMBER-GREEN-RED then will settle on RED if all self-tests are passed.
Press the connect switch on the BRM PCB and the 2 units will connect and automatically set-up a SCO voice
connection (duplex voice connection).
Press the “connect” button to disconnect the link.
DC Power
The unit can be powered by either 3xAAA batteries (for mobile operation) or by a DC power supply of between +7V
and +9V (300mA). If operating from 3xAAA batteries then the battery connect jumper JP1 must be fitted
Data Connector
A 9-way D-Type connector is provided to allow access to the RS232 data port on the BRM module. The functions
of the pins are as follows:
PIN
Number
1
2
3
4
5
6
7
8
9
Function
N/C
232-TXD
232-RXD
Vcc
GND
N/C
232-CTS
232-RTS
N/C
Output at RS232 level: BRM Transmit data to Host(1 start, 8 data, no parity, 1
stop, 115.2kBaud)
Input at RS232 level: BRM Transmit data from Host(1 start, 8 data, no parity, 1
stop, 115.2kBaud)
Can be used to supply 4.0 – 5.5V regulated when batteries not fitted
Ground connection for data and power
Input at RS232 level: +V = BRM will not send to Host, -V = BRM may send to
host
Output at RS232 level: +V = OK to send to BRM, -V = Not OK to Send to BRM.
Connect to CTS on Host
Comments
Other Information
For a detailed description of the BRM Module please see the following documents:-
BRM Datasheet:
BRM Programmers Guide:
DS360
DS361
The SCO voice link is transparent to any data link that may be set-up. When the "connect" button is pressed the unit
goes through the Bluetooth connect protocol of paging the remote unit, synchronising the hop sequences and
establishing a SCO link. There is automatic power control i.e. when the units are close the transmitted RF power will
be low and as they are moved apart the power will automatically increase to maintain the link.
When the RF power is at MAX (automatically) it is likely that a buzz of around 250Hz will be heard. This is due to the
Audio CODEC is not being screened and is susceptible to the transmitted RF. It is possible with careful consideration
to layout and decoupling to virtually eliminate this buzz.
The frequency hopping nature of the BRM will allow a link to be maintained even with severe interference.
The onboard antenna is an inverted-F type and will give a line-of-sight range of around 300M if the antennas of each
unit are pointed towards each other. The range can be greatly improved if the on-board antennas are removed (by
cutting the PCB along the drill holes) and a directional antenna fitted via a SMA RF connector.
DS362-2 Dec 03
©2003 Reg. No. 227 4001, England
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