Telephony API
The Microsoft Telephony API (TAPI) is an application interface used for accessing communications features such as connection monitoring. This API is used to provide services such as these without relying on the hardware to set them up. It ties in heavily to the Unimodem mechanism. TAPI functions completely independently from the device hardware. It is now used for modem data transfers; the COMM.API is used for these operations.
When modems were first becoming popular, they could be difficult to configure. You had to understand the settings to use, such as which COM port to set up; the system resources, such as IRQs and DMA channels; and modem baud rates. Each application that was to use this device had to be set up separately. This process could take a great deal of time and become complex quickly when you attempted to use advanced modem initialization strings. TAPI replaced this requirement by providing a standard interface with which the modem would communicate so that the interface could be set up once and all applications could use it.
TAPI also provides other features, such as multiple calling locations. You can set up connection profiles for different dial-up access numbers. You can also customize how the number is dialed. For example, suppose that you set up two separate connection profiles, one with call waiting enabled and the second without it. This setup enables you to manage multiple connections without having to reconfigure your modem setup every time you need a variation. To access the TAPI options, select Start | Control Panel | Printers And Other Hardware | Phone And Modem Options.
Requirements for a Remote Connection
Over the course of this tutorial, we have addressed several types of remote connectivity technologies. Each has its strengths and weaknesses along with its core functions. Some technologies provide features or functionality that you might not need or want. Understanding how each one works and its benefits and disadvantages enables you to recommend solutions to fit business needs. It is now time to pull all the information together to figure out what is required to make your remote connection work.
To provide access to a remote server or network, you must properly set up and configure several items. Each item depends on other items, and this connection will not work without them all. The following list contains the common components required to connect to remote resources.
- Dial-up networking client This client must be set up with the appropriate parameters defined.
- Remote server You must have a remote server to dial in to reach a remote network.
- User account (PPP, SLIP, RAS) You must have a valid ID and password on the remote server or network.
- Modem/ISDN You must have a hardware device that enables you to communicate with the remote host.
- Access protocol A network-layer protocol must be set up and configured properly to access resources on the remote server or network. Examples include TCP/IP, IPX, and NetBEUI.
