VGA to workstation monitor FAQ
Copyright 1997,1998 Tomi Engdahl
Configuring your operating system
DOS support
If the monitor is a multisync monitor which supports normal VGA frequencies (31.4 Khz horizonal rate, 60 Hz and 70 Hz vertical refresh rate) then the monitor should work without problems. There might be some problems that the picture might not be properly centered in all screne modes etc. Some cards have utilities for centing the picture, but those are rare.
If your monitor does not support standard VGA frequencies then the situation becomes more complicated. For DOS there is no standard procedure to make them work with fixed frequency monitors and it is a little bit hard to make those to work with all DOS applications relaiably, because those software sometimes access video cards quite directly. Some grpahics card makers supply utilities (adjusting tool and TSR driver) to adjust the refresh rates for DOS modes and those might help you to make your graphics card to work wit some fixed frequency monitors.
SVGA Text Mode for DOS should allow you to use a fixed-frequency monitor under DOS if your video card is good enough. SVGA Text mode is available at http://www.ff-net.demon.nl/hitachi/stm16dos.zip. The DOS version of Scitech Display Doctor makes possible to use custom refresh rates for DOS modes, so it is a good idea to check the free demo version of that commercial software package to see if it works for you.
If your fixed frequency monitor is TV or similar video monitor then you should check Tomi Engdahl's VGA to TV conversion information and circuit web pages and check if the drivers work for you.
How to identify the brand and model of your graphics card
Some of the utility programs need sometimes need some information of your graphics card. You'll need to do this typically when debugging problems or when you are looking for updated video drivers. An alternative option is to look carefully at the labelling on the video card and its components, but the advantage of this procedure is that it can be performed without the need to open up the system case. Use the following procedure steps:
- Get to an MS-DOS Prompt
- Enter the "DEBUG" Program (type "debug" and then press enter)
- Type the following, exactly to the debug prompt:
d c000:0010
- Now you will see the contents of the beginning part of the video BIOS ROM on the screen in hexadecimal and ascii formats. For most video cards, you will see the name of the manufacturer and information about the video chipset type and version number.
- n some systems you may need to scroll down further to find the information. Do this by typing just "d" and then {Enter}, one or more times. More information will display on the screen.
- Exit "DEBUG" by pressing "q" and then Enter to quit the debug program.
Windows 95
Checking the settings currently in use
To determine the resolution when working in Windows 95, follow these steps:
- 1. Point your mouse to the "Start" menu and give it a single left click.
- 2. Left click on Settings and then left click on Control Panel.
- 3. Double left click on the Display icon and wait for the Display Settings screen to open, then left click on the Settings tab at the top of the screen.
- 4. In the box called "Desktop Area" you can see how many pixels you are currently displaying. (640 x 480, 800 x 600, etc).
Depending on your graphics card and driver, you may have a tab at the top of your Display Settings screen that says "refresh." If you click on this, you can see your current refresh rate.
However, in many instances, you may not have this tab as an option. If this is the case, in the Settings screen where you saw your computer resolution, click on the button that says "Change Display Type." A screen will appear that tells you your "adapter type." This is the type of graphics board your computer has. If you contact the manufacturer of your board, either by phone or on the internet, you should be able to find out what refresh rate you are using.
Changing the monitor settings
First thing is to check if any of the ready made monitor types or the refresh rates matches your monitor settings. You then selects the correct resolution and right refresh rate and that's it. The monitor selecting can be done using the following procedure:
- 1. Position the mouse pointer to an open area of the WINDOWS 95 desktop and click the RIGHT mouse button.
- 2. Select PROPERTIES from the drop down menu.
- 3. When the DISPLAY PROPERTIES appear select the SETTINGS tab and click the CHANGE DISPLAY TYPE button (In WIN95B, OSR2 select ADVANCED PROPERTIES).
- 4. In the MONITOR TYPE area select a monitor type that matches the monitor connected to the display adapter.(In WIN95B, OSR2 select the MONITOR TAB and click the CHANGE button.
For finding the correct setting you might need for you particular RGB monitor you need to use calculator to calculate if the screen setting are what the monitor wants (calculate horizonal refresh rate from resolution and refresh rate etc.) and sometimes you need some experimenting to test which setting works best. If you want to configure your Windows to a specific refresh rate then you should read the Implementing Custom Refresh Rates in Windows�95 article from http://microsoft.com/hwdev/devdes/refresh.HTM. I have not tested those tricks described at the document.
Some graphics card drivers have extra options to more configure the card option than what Windows 95 normally allows. Graphics cards from Matrox (Millenium, Mystique, Millenium II) have exceptionally good configurability options in their graphics cards and they can be quite easily configured to send out picture at almost any refresh rate that a monitor would want it. Information how to configure Matrox cards under Windows 95 can be found at http://www.matroxusers.com/ and at http://www.hut.fi/Misc/Electronics/circuits/vga2tv/matrox_tv.html. Matrox Millenium hardware even support sync-on-green (no extra circuit needed). The sync-on.green support can be turned on on Millenium by changing the HSYNC and VSYNC setting to have value of 33 insted of the typical 0 or 1.
If you have some other graphics card which has drivers which do not support free user configurability then you can try if Scitech Display Doctor program from Scitech Software Inc can provide you the settings you need. Scitech Display Doctor support very many VGA chipsets and allows free user configuration of sync and refresh rates. Scitech Display Doctor is a commercial program but you can download a 21 day trial version from Scitech Software Web Site and see if it solves your interfacing problems.
Other commercial program which program which provides similar configuration possibilities is PowerStrip. Basically it is a simple toolbar and menu that pops up from the system tray provides configuration and fast access to your favorite display settings and allowes many extensions to stndard settings (like custom screen refresh rates).
HZ Tool is a freeware tool for Windows 95/98 that lets you set the refreshrate for all resolutions. With Hz Tool you can edit the properties of your monitor, which allows you to get the most out of it in refreshrates and resolutions. And get the refresh rates you want. Note that all graphics cards and drivers do not allow you to change the refresh rate or use unusual resolutions. The program gives you freedom to set whatever refreshrates and resolutions you want, but you have to make sure that both the graphics card and your monitor can handle it. Use this programs as all those tips in this page with precaution.
I have read the following Win95 tips from usenet news but I have not tested them myself (so be warned that there can be errors in them): One possibility is to modify the monitor refesh rates by editing the Windows95 settings. At least in Win95 version v4.00.953 (osr2) has refresh rate settings for all graphics adapters. Another option is to do the same manually by editing the windows driver configuration file monitor*.inf which can be found at c:\windows\inf directory. Try to find your own graphics controller from those configuration files and you can try to modify it's settings. After you have made the changes change your display type to to basic VGA and then back to your normal graphics adapter and the new refresh rates should be then updated to your drivers. If everything went right you gan get the refresh rate you want.
Windows 3.x support
Configuring the monitor
What you can do with your grapahics card and how you configure it depends entirely on the drivers which came with teh card. You should try to find a resolution snd screen refresh rate which will match your monitor parameters and then start to use it.
Scitech Display Doctor is also available for Windows 3.x and you can use it to set the screen parameters like in the Windows 95 version described in previous chapters.
Windows NT
If you have a graphics card made by Matrox (Millenium, Mystique or Millenium II) you can configure the card settings quite freely using the graphics driver settings which are similar to those in Windows 95 drivers.
Linux and Xfree86
Xfree86 is a X-windowing system for Linux (also for other free Unixes and some other operating systems). Xfree86 provides excellent configurability compared to many windows drivers. There are lots of options available and you can do almost anyhting your grpahics card supports. The downside of this is that the configuration of Xfree86 is not the easiest job, bt if you know what you do you can expect very good results with old workstation monitors. If you are using Xfree86 and plan to do your own monitor configuration (mode line for configuration file) I recomment you to read XFree86 Video Timings HOWTO from http://www.xfree86.org/3.3.3/VideoModes.html. Another good resource is Use your old Workstation Monitors with Linux/XFree86 which is available at http://cvs.anu.edu.au/monitorconversion/.
Scitech Software is also working for making a Linux version of their Display Doctor software.
Tomi Engdahl <[email protected]>