6 dos and other operating systems – Quatech Asynchronous Communications Adapter DSC-200/300 User Manual

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6 DOS and Other Operating Systems

The DSC-200/300 is not a direct drop-in replacement for a legacy serial port

because its base address and IRQ cannot be fixed at values such as 3F8 hex, IRQ 4
(COM1) or 2F8 hex, IRQ 3 (COM2), etc. Rather, the system BIOS assigns the address
and the IRQ in a plug-and-play fashion at boot time. Software which is to use the
DSC-200/300 must be able to accommodate any valid assignments of these resources.

For Windows and OS/2, the Quatech device drivers determine what the

resource assignments are and proceed accordingly. In other cases, however, the user
must intervene. The discussion below will center on DOS, but the concepts can be
applied to other operating systems as well.

Many DOS applications support user configuration of the base address and IRQ

of a serial port. Such applications can generally make use of the DSC-200/300. Older
applications, as well as some custom software, may use hard-coded standard legacy
serial port addresses. These applications will require modifications to support PCI
devices.

Custom applications for which the customer has source code can be modified to

make just a few PCI BIOS function calls to obtain all the necessary configuration
information. The PCI BIOS specification can be obtained from the PCI Special Interest
Group. Contact Quatech technical support for more information.

6.1.1 QTPCI.EXE

Quatech's "QTPCI" utility supplies the information required when modifying

the serial port settings of the application. This program should be run from real DOS,
not in a Windows DOS box.

Figure 15 shows the Basic Mode display for the DSC-200/300 after the "Q" key

has been pressed. In this example, the DSC-200/300 uses I/O base address FFA0 hex
and IRQ 3. The hardware revision of the DSC-200/300 is also displayed. Pressing the
"N" key will show similar information for all non-Quatech PCI devices in the system,
including those devices integrated on the motherboard.

Quatech DSC-200/300 User's Manual

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