Advanced Call Center

COM port, TAPI or Way2Call ?

During setup, the Call Corder provides with selection of one of two modes: direct COM port access or standard TAPI interface. Later you can change the mode in Properties -> Telephone Device. TAPI stands for Telephony Applications Programming Interface. Your selection is critical both for compatibility and for troubleshooting.

In few words, the difference is as follows:

Advantages Drawbacks
Direct COM port access Full support of all modem features. Modem is grabbed by the Call Corder and is not available for other applications.
TAPI Modem or telephony card is easily shared between multiple applications. Most (yet not all) features are supported.

Direct COM port access

Direct COM port access

The direct COM port access allows full use of all modem features. In case you decide to use this mode, it is critical to specify your modem type correctly to let the program make use of all its enhancements, because each modem type possesses its own directive set (often incompatible with others). It is true even for modems of one family (made with different revisions of the same chipset)! There are tons of various different modems in the world, thus the program often fails recognizing a rare brand correctly. As a result, the program operation may fail.


Theoretically, one can avoid all these problems by using Telephony Applications Programming Interface (TAPI) standard. The idea of such an interface is not revolutionary but yet quite smart. However, this interface implementation is yet far from ideal. For example, faxing is not provided at all, voice operation is quite unstable, etc. But - now a software needs not to know about modems, phone sets, etc. (including ISDN, DSL, and modem raiser cards)! TAPI will do everything to let a software work with all hardware brands in the same way.

Unfortunately, all this is too theoretical and academic by now. In practice, however, modems are often supplied with wrong drivers, of these drivers operate wrong, or the OS itself is wrong. For instance,

Windows 95 supports voice modems only after installing Unimodem/V module you need to download from Microsoft server.

Windows NT 4.0 does not support voice modems at all.

Windows 98 has a complete set of drivers and is the only OS of Windows family that operates normally in TAPI mode (provided you install the right driver correctly).

Windows 2000 requires several updates of voice mode drivers in comparison with '98, so voicing is still in question here.

So if one mode does not work, select another at Properties -> Telephone Device.

The good news for TAPI is that one great problem gets resolved: sharing your modem between software applications. Thus, in TAPI mode you can login to the Internet or get a FAX via any other application - without exiting Call Corder (the direct COM access mode prevents other programs from accessing your modem when Call Corder is run).

Current versions of Call Corder doe not support the following features in TAPI mode:

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