User's Manual

Operating the RB540MB for Standard RX

The RB540-a/c has optional firmware for Standard HFP+A2DP Stereo RX. This firmware allows

the user to establish a Bluetooth stereo connection between a RB540-a/c module and a Bluetooth

capable cell phone. After a Bluetooth connection is established with the phone, the user can pick up

a phone call or play music from his phone.

The following will explain how to use the RB540MB switches to control the RB540-a/c module

with the standard HFP+A2DP RX firmware.

Connect a microphone, speaker and USB cable into RB540MB board.

1. Power ON: After turning on Power Switch PSW1, the LED 1–4 will flash once and light from

LED1 – LED2 – LED3 – LED4, then LED4 – LED3 – LED2 – LED1, then all LED1–4 will

flash for 2 times. If no paired before, the module will automatically start pairing and enter

discoverable mode. If paired before, the module will immediately look for the previously

paired device and try to reconnect. After 5 minutes, no Bluetooth Connection is established, the

module will go to standby mode and the LED1 will flash every 2 seconds.

2. Initiate Pairing: When the module is in standby mode, press button SW4 for 5 seconds to

initiate entering discoverable and pairing. If pressing longer than 10 seconds, the BT module

will clear paired device and look up for new BT device again. During the pairing, LED1–4 will

flash on and off at 0.5 second rate.

Turn on BT mode in your phone, and go to search mode. You can use phone to connect

RB540MB. The device name to search for RB540-a is "Std RX v21.004", and for RB540-c is

“Std RX v22.004”. After paired, LED1–4 will flash 5 times and then LED1 will flash at

1second rate while LED 2-4 off. Once connected, as shown on your phone, you can start to

play music to RB540MB.

3. Play Music: Plug your speakers into the SP-R and SP-L two pin headers or into the SPK1

Stereo Jack. There is no polarity. Go to your phone application and start playing music. There

are 10 levels of volume up and down. SW2 is volume + and SW1 is volume -. It will have a

warning sound when reaching maximum volume. Button SW2 and SW1 can be pressed step

by step or continuously. You can also use phone to change speaker volume.

4. Hands Free Phone Operation (HFP): The RB540MB can also be used for hands free phone.

Use button SW3 for call pick up/ end call, once you hear ring tone from speaker, plug

microphone and speaker for your hand free device.

Incoming call: when incoming call, the 4 LEDs will flash 8 times. It will repeat until the call is

pick up, go to voicemail or disconnect. After pick up call, LED 1-4 will flash from LED1 –

LED2 – LED3 – LED4, then LED4 – LED3 – LED2 – LED1 periodically.

End call: After picking up the call, if press SW3 button will disconnect the call. Music resumes

after call ends.

Power cycle RB540MB or switch off-and-on the cell phone Bluetooth, the module will automatically

connect to the cell phone.