Lines, Channels, and Addresses

In POTS, exactly one channel exists on a line, and this is used exclusively for voice. With ISDN, at least three (and as many as 30 or more) channels can exist on a line simultaneously. Currently, most TAPI functionality involves POTS applications that handle a single line using its single channel because ISDN hardware is not yet widespread. In POTS, an application that wants to transmit data would communicate over one line, and a voice application would communicate over another linepics/TAPI00090000.gifboth of these applications could use the same line, but if so, not at the same time.

In general, one line has exactly one address (telephone number). In cases where lines carry two or more channels, each channel can have its own address, which means that a line has as many addresses as it has channels. TAPI assigns Address IDs to these different addresses to make it easier to manipulate them.

Software for developers
Delphi Components
.Net Components
Software for Android Developers
More information resources
Unix Manual Pages
Delphi Examples