Building on the project in part 1, we’re going to expand our project to extract the device’s Model and Serial Number!

Once again, I’ll be using an ONTRAK ADU208 as my test device, but similar steps should work with other USB HID devices too.

In part 1, we created a function that gets called every time a matching device is connected to the system. At present, this function simply logs the device ID to the console. Let’s modify that function to store the Name and Serial Number, then log them to the console:

// New USB device specified in the matching dictionary has been added (callback function)

static void Handle_DeviceMatchingCallback(void *inContext,

                                             IOReturn inResult,

                                             void *inSender,

                                             IOHIDDeviceRef inIOHIDDeviceRef){

// Retrieve the device name & serial number

NSString *devName = [NSString stringWithUTF8String:

                                              CFStringGetCStringPtr(

                                                   IOHIDDeviceGetProperty(inIOHIDDeviceRef,

                                                        CFSTR("Product")),

                                                        kCFStringEncodingMacRoman)];

NSString *devSerialNumber = [NSString stringWithUTF8String:

                                            CFStringGetCStringPtr(

                                               IOHIDDeviceGetProperty(inIOHIDDeviceRef,

                                                     CFSTR("SerialNumber")),

                                                       kCFStringEncodingMacRoman)];

// Log the device reference, Name, Serial Number & device count

NSLog(@"\nONTRAK device added: %p\nModel: %@\nSerial Number:%@\nONTRAK device count: %ld",

     inIOHIDDeviceRef,

     devName,

     devSerialNumber,

       USBDeviceCount(inSender));

}