The following terms and abbreviations are used throughout this section.
TAPI Telephony Application Programming Interface – a component of Microsoft operating systems. The TAPI interface allows the connection of a PC running Windows to telephone services. The TAPI standard supports connections by individual PCs, as well as LAN connections serving many computers. Within each connection type, TAPI defines standards for simple call control and manipulating call content.
The Modem Manager provides services that allow modems connected to different machines to be managed as a common pool.
Key features of the Modem Manager are:
Modem Manager can control a pool of modems distributed across a number of PCs.
• Outgoing calls are queued and then executed at the requested time.
• The modem pool is managed so as to "round-robin" the available modems.
• All modem access uses the Microsoft TAPI interface; thereby allowing the modem pool to be shared with other applications.
• Incoming calls are initially routed to a driver discriminator routine that inspects the initial data packet and indicates whether it wishes to accept the call, and which driver instance should handle it.
• Modems may be shared among different drivers, and even among different VTS applications.
• Incoming calls may be screened, and if not destined for any VTS driver, passed on to other applications.
• Call setup and progress information is distributed to all copies of Modem Manager on a networked system so that drawing methods function on all machines.
• Call queue information is distributed to all copies of the Modem Manager on a networked system so that queue integrity is maintained, even after switching to a backup server.
• Support for voice modems is integrated providing DTMF digit detection and text-to-speech translation on output.
• It is possible to exclude one or more local modems on a workstation from the modem pool configuration. These can then be used as a preferred outgoing route.
• It is possible to assign arbitrary properties to a modem or group of modems, and to request a match with these properties when initiating a call.
The Modem Manager interfaces with a Microsoft system component called "TAPI". TAPI allows different modems to be handled in a generic manner, and to be shared between different applications and services (e.g. RAS, and/or FAX). TAPI does not interface directly to the modem; this is the job of the Trihedral Voice Modem Service Provider. You may use the Unimodem V instead but, the Trihedral driver was developed to avoid several problems that have been found with the Unimodem V driver.