Following is the quick function reference for TAPI functions categorized by the three levels of telephony services: Basic, Supplementary, and Extended. Also included in this section is the quick function reference for the related Assisted Telephony services. See the overviews for Assisted Telephony and Service Levels for expanded discussion.
Basic Telephony Services Reference discusses TAPI functions associated with POTS-level telephony tasks.
Supplementary Telephony Services Reference discusses TAPI functions with more advanced features such as hold and transfer.
Extended Telephony Services Reference discusses functions that enable the user to access service provider-specific functions not directly defined by TAPI.
Assisted Telephony Services Reference discusses functions designed to let any Microsoft® Win32®-based application establish voice calls and media calls, such as in using a phone dialer.