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I have an RN-41 bluetooth module connected to an MSP430. I want to connect the RN-41 to an Android cellphone. Just by having power to the Bluetooth module, the cellphone finds the device. However, it is not able to make pairing the only documentation that I find about pairing on the RN-41 says that the default key for pairing should be 1234. In any case the cellphone doesn't even ask for the pass key but shows an error saying that is not able to pair. Can anyone provide some guidance?

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  • \$\begingroup\$ I just have connected Rx,Tx to the msp. Vcc & Gnd. Also input PIOs are grounded, and the reset pin is connected to Vcc \$\endgroup\$
    – Sednus
    Oct 22 '11 at 4:57
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The problem I was actually having with the module, was a hardware problem. I tried to connect the Bluetooth module power to the VCC pin of the target board of the MSP. It is a 3.3v source, which is appears to be compatible. But the maximum current that could pass through that pin was 15mA, which is enough to set the device discoverable but it stays short when trying to establish a connection (needs around 35mA). Hence, I was able to see it, but got an error upon establishing a connection. Hope this helps somebody else in the future.

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It has been a while since I messed with my RN41 connecting to an android phone, but I will try to provide some advice for you.

The bluetooth module uses SPP (Serial Port Profile) as its default profile. Essentially the way that it works is it opens up a serial port tunnel that can be used just as if you were using a RS232 connection on a computer. The problem with this profile is that it isn't always fully support because it isn't commonly used in consumer products. Here is a StackOverflow post that talks about it a bit.

You can verify that it isn't a hardware issue by connecting it to a computer that supports SPP.

Depending on your goals, it may be better for you to use a different bluetooth profile which is described in the datasheet starting on page 18.

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  • \$\begingroup\$ I hope it helps, sorry for the very delayed response. \$\endgroup\$
    – Kellenjb
    Nov 21 '11 at 19:36

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