Unimodem is a TAPI service provider that was written by Microsoft and is incorporated directly into both Windows 95 and Windows NT.. The Unimodem service provider is designed to support an extremely wide range of modems and faxmodems under both these operating systems. The TAPI functionality that Unimodem provides is very limited; providing only the support needed for relatively simple applications such as the Microsoft Network, Internet Explorer, the Windows HyperTerminal application, etc. Unimodem does not provide any support for detecting or answering an incoming call, or for detecting when a call has disconnected. Unimodem also can not detect DTMF digits, nor can it play or record audio files over a phone line.
Unimodem/V is a TAPI service provider that was written by Microsoft and released for general use in November 1995. Unimodem/V supports the same functionality as Unimodem, but also supports the detecting of DTMF digits, the detection of incoming calls, and the ability to play and record audio files over the phone line.
Unimodem/V is currently only supported under Windows 95 with TAPI 1.4. A new version of Unimodem/V is supposed to be available with Windows NT 5.0 is available.
Unimodem/V currently supports a small but growing number of hardware platforms. Because the platforms supported by Unimodem/V can change without notice the platforms are not listed here. To determine if your voice modem is supported by Unimodem/V, read the README.TXT file included with Unimodem/V or contact your modem vendor. If your modem is not listed in the README.TXT file then chances are you will need a modem information file (*.inf) from your modem vendor in order to use Unimodem/V. You can download Unimodem/V from the following location:
http://www.microsoft.com/hwdev/modem/
Unimodem/V is capable of detecting when a call disconnects only in very specific environments. Most residential telephone systems indicate that a call has disconnected by what is known as a loop current drop. This means that the actual electrical current on the telephone line is reduced by a specific, detectable amount. Unimodem/V is not capable of detecting loop current drops, so it can not tell if a call has been disconnected in this type of environment. The only way Unimodem/V can detect when a call has disconnected is if a fast busy tone is detected on the telephone line. Many PBX's and some telephone companies generate a fast busy signal on a phone line to indicate the call has disconnected.
3. What is the Operator Agent and how does it work?
The Operator is an application that is integrated with Unimodem/V and provides a means of manual call discrimination. Unimodem/V can not determine on it's own if a call is a voice, fax, or datamodem call so it relies on the Operator to do this. The Operator only works with Unimodem/V and only with voice modems supported by Unimodem/V.
If the Operator is used (see the Unimodem/V documentation for usage instructions) then a telephone icon will appear in the system tray of your menu bar. Placing the mouse cursor over this icon will display the message "Idle, not monitoring line". The Operator will remain in this idle state unless TAPI applications are running. If only one TAPI application is running then the Operator will continue to remain idle. This is simply because if only one TAPI application is running then Unimodem/V knows exactly what application all calls should be directed to.
If two or more TAPI applications are running, and the two applications are interested in different types of media (i.e. a voice application and a fax application) then the Operator will become active. At this point if you place the mouse icon over the Operator icon the message "Monitoring line for VOICE, FAX" will appear. The Operator can be set up to redirect calls in two different ways. If your modem supports distinctive ringing and is configured properly with Unimodem/V then it can automatically direct the call to the appropriate application based on the pattern of the ring.
The other method Unimodem/V uses is a voice menu. If a call is made into Unimodem/V then the Operator will answer the call and ask the caller to press a digit to identify the type of call (voice, fax, or data). The Operator will then pass off the call to the appropriate TAPI application.
4. Unimodem and Unimodem/V developer information.
Microsoft has some information available for modem vendors that describes Unimodem and Unimodem/V in detail, including how to write .inf files for modems. See the files at ftp://ftp.microsoft.com/developr/drg/Modem/ for all the details.
5. Where can I get Unimodem/V?
You can download Unimodem/V directly from Microsoft at:
http://www.microsoft.com/hwdev/devdes/modemddk.htm
6. Why doesn't Unimodem/V return correct CallerID information?
Earlier versions of Unimodem/V had a buffer that could only store 10 digits of CallerID information. For the US and Canada 10 digits was enough because of the format of telephone numbers in these countries. However a number of other countries have telephone numbers that can exceed 10 digits, which would overflow this buffer in Unimodem/V. Microsoft fixed this problem with an updated version of Unimodem/V, so any version of Unimodem/V dated December 19, 1996 or later can support CallerID strings of greater than 10 digits.
7. How can I determine if Unimodem/V is installed?
The easiest sure fire way to determine if Unimodem/V is installed is to open a datamodem line and see if it also include an audio device by calling lineGetID with the "wave/out" device class.
If you need to determine whether Unimodem/V is installed without actually using TAPI (such as during the installation of a program) then you will need to check the version number of specific system files. See http://209.66.99.126/dll/dll_version.shtml for information on doing this. Note that this information is specific to Unimodem/V with TAPI 1.4 under Windows 95. The information in this page may not be accurate for systems that have had TAPI 2.1 installed, nor is it likely to be accurate on Windows NT.
8. What are the different versions of Unimodem/V?
To determine the version number of Unimodem or Unimodem/V start the Windows Explorer and locate the file unimdm.tsp in your Windows\System directory. Hit ALT+Enter to display the file properties and click on the Version tab. The version should be one of those listed below (these are for Windows 95 only, not Windows NT):
Unimodem
Version 4.00.950 (Original Win95 release)
Unimodem/V
Version 4.10.431 (Unimodem/V downloaded from MS - November 1995 release)
ftp://ftp.microsoft.com/Softlib/MSLFILES/unimodv.exe
Version 4.10.431 (Win95 OEM Service Release 2)
Version 4.10.1343 (UnimodemV downloaded from MS - December 1996 release)
http://www.microsoft.com/hwdev/download/devdes/a5582.zip
Version 4.10.1650 (Windows 98, Beta 3)
9. Are Unimodem/V and Unimodem/5 the same thing?
NO! The 'V' in Unimodem/V stands for "voice", not the Roman numeral V. Unimodem/V is Microsofts voice modem TSP for Windows 95. Unimodem/5 is the name that Microsoft has given to the generic modem TSP that will be part of Windows NT 5.0.
10. What modems are supported by Unimodem/V?
Unfortunately there isn't a single comprehensive list of all the modems supported by Unimodem/V. The reason for this is that the individual voice modem vendors are responsible for providing the modem information files (*.inf) that configures Unimodem/V to work with their specific modem. As new voice modems come on the market the information hopefully will eventually make it to the microsoft.public.win32.programmer newsgroup. I have collected some of the posts from individuals who have tested Unimodem/V with different voice modems. Their posts can be found here.