The TAPICLIENT_LineSetLineDevStatus function is called during a call to the lineSetLineDevStatus function.
LONG TAPICLIENT_LineSetLineDevStatus(
HMANAGEMENTCLIENT hmClient,
LPTAPIPERMANENTID lpPermanentID,
DWORD dwStatusToChange,
DWORD fStatus
);
lineSetLineDevStatus, TAPICLIENT_ClientInitialize, TAPIPERMANENTID