Opening and Closing Phone Devices

After determining the capabilities of a phone device, an application must open the device before it can access functions on that phone. After a phone device has been successfully opened, the application is returned a handle representing the open phone. A phone device can be opened in different modes, thus providing a structured way of sharing a phone device.

The phoneOpen function opens the specified phone device to give the application access to functions on the phone. A phone device is identified to phoneOpen by means of its device identifier, which is passed as the dwDeviceID parameter.