The PHONEHOOKSWITCHDEV_ bit-flag constants describe various audio I/O devices each with its own hookswitch controllable from the computer.
No extensibility. All 32 bits are reserved.
These constants are used in the PHONECAPS data structure to indicate the hookswitch device capabilities of a phone device. The PHONESTATUS structure reports the state of the phone's hookswitch devices. The function phoneSetHookSwitch and phoneGetHookSwitch use it as a parameter to select the phone's I/O device.