How Can I Establish A L2Capp Interrupt Channel Connection?

Question

Im trying to open a L2Cap HID Channel And Interrupt channel so I can send HID commands to a bluetooth device.

I've done all my service advertising and device paring and established a baseband connection.

The Hid Control channel opens fine. When I try to create my kBluetoothL2CAPPSMHIDInterrupt connection

l2capChannelQueueSpaceAvailable

delegate method called (not sure what this means) followed by

l2capChannelOpenComplete

but the connection closes immediately calling

l2capChannelClosed

How can I correctly open these connection?

I've spent a long time digging through the IOBlueTooth framework and the bluetooth.org HID spec but theres barely any helpful information (that I can find at least).

When i trace out my L2Cap channels I see some null values for

mIncomingDataListener

and

mEventDataListener

. I dont know how to set these or if they have anything to do with my problem.... just speculating.

The code snippet below is my attempt so far to make the connections after a connection to the device has been established.

-(void)establishL2CappConnections:(IOBluetoothDevice*)device
{
    IOReturn r;
    IOBluetoothL2CAPChannel *ch1;
    r = [device openL2CAPChannelSync:&ch1
                             withPSM:(BluetoothL2CAPPSM)kBluetoothL2CAPPSMHIDControl
                            delegate:self];
    self.mL2CappChannel=ch1;
    NSLog(@"r == %i",r);

    IOBluetoothL2CAPChannel *ch2;
    r = [device openL2CAPChannelSync:&ch2
                             withPSM:(BluetoothL2CAPPSM)kBluetoothL2CAPPSMHIDInterrupt
                            delegate:self];
    self.mL2CappInterruptChannel=ch2;
    NSLog(@"r == %i",r);


}

Edit:1

I've attached my packet logs. It's strange, a request for

kBluetoothL2CAPPSMSDP 0x0001

gets made without me requesting it and then everything starts disconnecting.

BT Packet Logs

Answer 1

As per your logs its very clear that your device in in Limited Connection mode, its stays Active for 30sec or less. change device settings to make it General Discoverable.

kBluetoothL2CAPPSMSDP 0x0001

means Bit 13 - Limited Discoverable Mode

Playing with the Bluetooth settings will solve your problem