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Linux Journal: The Linux Telephony Kernel API

“A year ago, Internet Telephony was a curiosity, and many people
thought it would never work for real phone calls. Now, with
services like Net2Phone, Deltathree.com and DialPad providing free
or extremely low-priced phone calls delivered via the Internet,
Voice over IP (VoIP) has reached near-mainstream status. While
Linux clients for those services are not yet available, Linux is
not being left behind. With the 2.2.14 kernel, Linux has taken a
bold lead in the area of computer telephony integration: we have
the first modern operating system with a defined kernel-layer
application programming interface (API) for telephony support. To
sweeten the pot, excellent quality open-source telephony software
is already using this API. You can call around the world using
Linux and the Internet–and the call is free!”

“This article will explain the basics of how the telephony
device drivers are integrated into the kernel in a way suitable for
creating a common API across vendors. Then we’ll discuss the basic
ideas behind the design and function of the API, and how data and
event information are dealt with separately. Finally, we’ll discuss
how telephony events (like ringing or picking up a handset) are
handled in a process called “asynchronous event notification.”

Complete
Story

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