TAPI OS Design Development (Windows CE 5.0)

Article
09/14/2012

The Telephony API implementation in Windows CE is a subset of the Microsoft Telephony Application Programming Interface (TAPI) version 2.0 and some parts of TAPI version 2.1. TAPI provides an application programming interface (API) that simplifies and abstracts the details of making telephony connections between two or more devices. TAPI abstracts call-control functionality to allow different, and seemingly incompatible, communication protocols to expose a common interface to applications through its support of telephony service providers (TSPs).

Windows CE provides one TSP, the Universal Modem (Unimodem) service provider, which supports AT-command-based modems. Windows CE supports installable service providers, which allows you to add additional TSPs under TAPI — for example VoIP, such as H323 and Session Initiation Protocol (SIP), Integrated Services Digital Network (ISDN), and cell phones.

The Unimodem driver serves as an example of a service-provider implementation. You can also create a customized Service Provider Interface (TSPI) by using the TSPI API set.

OS Design Information

The following table shows operating system design information for the Telephony API.

Concept	Description
Dependencies	Minimal GWES and Device Manager
Hardware considerations	None

Modules and Components

The following table shows the components and modules that implement Telephony API.

Item	Module	Component
Telephony API (TAPI 2.0)	tapi	tapilib
Unimodem support	unimodem	None

Telephony API Implementation Considerations

The following table shows the Sysgen variables for TAPI 2.0.

Sysgen variable	Description
SYSGEN_TAPI	When this variable is set, the Telephony API (TAPI 2.0) Catalog item is included in the OS design.
SYSGEN_UNIMODEM	When this variable is set, the Unimodem support Catalog item is included in the OS design.