Applications whose telephony functionality goes beyond the most basic call
control or are meant to handle inbound calls must be built using the Telephony API
(not Assisted Telephony). The Telephony API defines three levels of service:
- The elementary level of service, called Basic Telephony, which provides a
minimum set of functions that corresponds to Plain Old Telephone Service (POTS).
TAPI service providers are required to support all Basic Telephony functions.
- The Supplementary Telephony level of service, which provides advanced switch
features such as hold, transfer, and so on. All supplementary services are
optional; that is, the service provider is not required to support them.
- The Extended Telephony level of service, in which the API provides
well-defined API extension mechanisms that enable application developers to access service
provider-specific functions not directly defined by the Telephony API.
- Software for developers
Software for Android Developers
- More information resources
Unix Manual Pages