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Modems & DOS-compatibility

*** CONEXANT HSF/Soft56 DOS-Support Problem - See Special Report.

The vast majority of modems sold or included with systems today are controllerless (aka software modem, soft modem, Winmodem, HSP) using PCI, USB or AMR interfaces.

A controllerless modem requires an operating system specific driver in order to work. DOS is not a supported operating system for any of these modems: You cannot boot up the machine with MS-DOS and utilize this type of modem.

You can run most legacy DOS application programs in Windows - aka DOS Box. [Start->Run->Command gives you an MS-DOS 'machine'. ]  

If the legacy DOS application is designed to use a modem - there may be a problem: Controllerless modems do not use a standard COM port - they create their own virtual port. If the modem cannot be accessed using legacy IBM-PC interrupts and I/O ports, the modem portion of the DOS application will fail.

It is possible for a controllerless modem to support legacy DOS applications in a Windows DOS Box: some modems come with DOS support. TurboComViP can be purchased to provide DOS-box support for most controllerless modems that otherwise lack such support. (For Windows 95/98 only; ViP doesn't support Windows NT,2k, or ME.)


All Lucent-based Apollo/Mars - Lucent Win Modem
Lucent-based WildWire
Lucent Scorpio (AMR/Soft)
Some 3Com/USR*
Some Rockwell/Conexant HCF & HSF Modems*


Some 3Com/USR Winmodems*
Some Rockwell/Conexant HCF/HSF Modems*

DOS Support Unknown**:

Some 3Com/USR
Motorola SM56 (User reporting works in Windows Dos-box)
PCTel (have user reporting in Dos-box & Win98; doesn't work in Win2k)
ST Micro/SGS

* - Both 3Com/USR and Rockwell/Conexant have licensed PCW TurboViP technology; however, the ViP drivers are included but not correctly implemented with some Conexant-based modems. Not all 3Com/USR drivers for controllerless modems include the ViP drivers - I'm seeking more information on both situations....

** - If you have tested DOS-box support with any of these modems, please let me know.

WORTH A TRY: Some DOS applications that give you trouble with modem communication may operate better if you install the DOS application through Windows Control Panel -> Add/Remove Programs - Install... button. (This will not enable a modem that has no DOS support to work, but it may solve some problems with particular DOS applications that have lock-up or communication trouble with a modem that does support DOS-box operation.)

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