This function indicates if the device does or does not exist using its Address property (See also DeviceExistsCode).
Description: This is the device address, such as "Unit1", "0F47ED78-2", or "U2-I45-K2.2"
Description: When True, the address must match exactly. When false, the address match is case insensitive such that apple2=APPLE2
Return value: status
Type: long (.NET Integer)
Description: Returns -1 if the device does not exist, otherwise it returns the device reference ID number of the device. The reference number can then be used with the GetDeviceRef function.