The phoneSetVolume function sets the volume of the speaker component of the specified hookswitch device to the specified level.
LONG phoneSetVolume(
HPHONE hPhone,
DWORD dwHookSwitchDev,
DWORD dwVolume
);
Returns a positive request identifier if the function is completed asynchronously or a negative error number if an error occurs. The dwParam2 parameter of the corresponding PHONE_REPLY message is zero if the function succeeds or it is a negative error number if an error occurs. Possible return values are:
PHONEERR_INVALPHONEHANDLE, PHONEERR_NOMEM, PHONEERR_NOTOWNER, PHONEERR_RESOURCEUNAVAIL, PHONEERR_INVALPHONESTATE, PHONEERR_OPERATIONFAILED, PHONEERR_INVALHOOKSWITCHDEV, PHONEERR_UNINITIALIZED, PHONEERR_OPERATIONUNAVAIL.
Version: Use TAPI version 1.4 and later.
Header: Declared in tapi.h.
Import Library: Link with tapi32.lib.
TAPI Reference Overview, Supplementary Phone Services Functions, PHONE_REPLY