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iPad is transmitting a 0x71 packet immediately after connecting over the control L2CAP channel in a Bluetooth HIDP connection.

Unless I respond with 0x00 byte immediately, over the same channel, iPad disconnects.

What does 0x71 mean? I cannot find this byte in HID specification nor in Bluetooth HIDP specification, although I might just be searching poorly. I have some indication it might be the set_protocol packet, probably setting to REQUEST protocol as opposed the BOOT protocol, but I can't confirm that.

I don't think it matters much that I'm connecting OS X machine with the iPad, with OS X machine serving as the server, but I'm noting it here in case it does.

Charles
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Ivan Vučica
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1 Answers1

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0x71 means "SET_PROTOCOL for Input reports". One can choose between Boot mode (0x70) and regular mode (0x71). See 7.4.6 of the HID_SPEC_V10 from Bluetooth.org for more details.

mringwal
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