The PHONEEXTENSIONID structure describes an extension identifier. Extension identifiers are used to identify service provider-specific extensions for phone device classes.
typedef struct phoneextensionid_tag {
DWORD dwExtensionID0;
DWORD dwExtensionID1;
DWORD dwExtensionID2;
DWORD dwExtensionID3;
} PHONEEXTENSIONID, FAR *LPPHONEEXTENSIONID;
No extensibility.
Extension identifiers are generated using an SDK-provided generation utility.
Version: Use TAPI version 1.4 and later.
Header: Declared in tapi.h.