I try to refresh the SDP data for a Bluetooth device that has reconnected. So when I receive connect notification I call -[IOBluetoothDevice performSDPQuery:] passing object, that should receive the query completion call. What I observe is that sdpQueryComplete:status: is not being called, buit calling performSDPQuery causes additional connect notification to be dispatched. Running this under debugger results in some weird log line: [IOBluetooth] **** This currently won't trigger SDP delegate I run this code on Sequoia 15.5

I wonder how one would use IOBluetoothHandsFree APIs to interact from macOS app with a bluetooth device that implements bluetooth hands free profile. My current observation is as follows: IOBluetoothDevice object representing the device correctly identifies it as a hands free device, i.e.: there is a proper record in services array, that matches the kBluetoothSDPUUID16ServiceClassHandsFree uuid, the IOBluetoothDevice handsFreeDevice property returns 1 Attempt to create IOBluetoothHandsFreeDevice using IOBluetoothDevice as described above (i.e. [[IOBluetoothHandsFreeDevice alloc] initWithDevice: myIOBluetoothDeviceThatHasHandsFreeDevicePropertySetTo1 delegate: self]) results in the following output in debugger console: SRS-XB20 is not a hands free device but trying anyways. Subsequent call to connect on an object constructed as above results in the following stream of messages: API MISUSE: <CBClassicPeer: 0x1442447b0 6D801974-5457-9ECE-0A9B-8343EC4F60AA, SRS-XB20, connected, Paired, b8:d5:0b:03:62:70, devType: 19, PID: 0x1582, VID: 0x0039> Invalid RFCOMM CID -[IOBluetoothRFCOMMChannel setupRFCOMMChannelForDevice] No channel <IOBluetoothRFCOMMChannel: 0x600003e5de00 SRS-XB20, b8-d5-0b-03-62-70, CID: 0, UUID: 110F > AddInstanceForFactory: No factory registered for id <CFUUID 0x600000b5e3e0> F8BB1C28-BAE8-11D6-9C31-00039315CD46 -[IOBluetoothRFCOMMChannel setupRFCOMMChannelForDevice] No channel <IOBluetoothRFCOMMChannel: 0x600003e5de00 SRS-XB20, b8-d5-0b-03-62-70, CID: 0, UUID: 110F > API MISUSE: <CBClassicPeer: 0x1442447b0 6D801974-5457-9ECE-0A9B-8343EC4F60AA, SRS-XB20, connected, Paired, b8:d5:0b:03:62:70, devType: 19, PID: 0x1582, VID: 0x0039> Invalid RFCOMM CID Note that this device's handsFreeServiceRecord looks as follows: ServiceName: Hands-free unit RFCOMM ChannelID: 1 Attributes: { 0 = "uint32(65539)"; 256 = "string(Hands-free unit)"; 9 = "{ { uuid32(00 00 11 1e), uint32(262) } }"; 785 = "uint32(63)"; 1 = "uuid32(00 00 11 1e)"; 6 = "{ uint32(25966), uint32(106), uint32(256) }"; 4 = "{ { uuid32(00 00 01 00) }, { uuid32(00 00 00 03), uint32(1) } }"; } and explicit attempt to open RFCOMM channel no 1 ends like this: WARNING: Unknown error: 911 Failed to open RFCOMM channel -[IOBluetoothRFCOMMChannel setupRFCOMMChannelForDevice] No channel <IOBluetoothRFCOMMChannel: 0x6000002036c0 SRS-XB20, b8-d5-0b-03-62-70, CID: 1, UUID: 111E > AddInstanceForFactory: No factory registered for id <CFUUID 0x600003719260> F8BB1C28-BAE8-11D6-9C31-00039315CD46 -[IOBluetoothRFCOMMChannel waitforChanneOpen] CID:1 - timed out waiting to open -[IOBluetoothDevice openRFCOMMChannelSync:withChannelID:delegate:] CID:1 error -536870212 call returned: -536870212