4825 SX (250-5141/52) Video Faxback Doc. # 1692 The video circuitry for the Tandy 4825SX is included on the main logic board. This circuitry features: * IBM VGA compatibility plus support for Super VGA modes with 132-column text and both 800 x 600 and 1024 x 768 resolution graphics * Support for VESA Super VGA BIOS Extension Version 1.0 specification * A color palette of more than 262,000 possible colors * Compatibility with both monochrome and color, fixed and multiple-frequency analog monitors (including 8514/A-compatible monitors) MONITOR AND SOFTWARE COMPATIBILITY The video circuitry is compatible with software written for the following video standards on color or monochrome VGA analog monitors: * VGA (Video Graphics Array) * VESA Super VGA * MCGA (Multi-Color Graphics Array) * EGA (Enhanced Graphics Adapter) * CGA (Color/Graphics Adapter) * MDA (Monochrome Display Adapter) * Hercules graphics (Hercules Graphics Card) CONFIGURING THE APPLICATION SOFTWARE Many application software packages include a program that prepares the application for use with your particular hardware. you can reconfigure many applications without re-installing them. You can also configure applications during installation. NOTE: Before installing drives, make copies of the original Installation diskettes. The Drivers diskette must be write-enabled. The VGA 1024 NI Drivers Diskette contains drivers for many applications. To install a driver, follow these steps: 1. Insert the Drivers Diskette into Drive A. 2. Type a: and press ENTER. 3. Type install and press ENTER. 4. To view the documentation, type a: and press ENTER, and then type readme and press ENTER. 5. To print the documentation, type a: and press ENTER, and then type printme and press ENTER. NOTE: To use the highest resolution VGA modes with several popular applications, you must use the VGA 1024 NI drivers. Follow the tips below for best results. * Video drivers for common applications are included on the Drivers diskettes. See the README file included with the drivers and the documentation included with the application software. * To get the sharpest display, select the highest resolution mode available when you install your application software packages. * Install your software for VGA or EGA if possible, so that the software runs in the video circuitry's default configuration. * If your software does not provide a VGA or an EGA option and you are using a color monitor, try installing the software for color, if available. This usually works with the video circuitry's default color mode on color monitors. * If you software supports a video standard other than EGA or VGA, configure the software for the best standard. Run VGAMODE.EXE and set the emulation mode to match the program. OPERATION The video circuitry, in its default configuration, supports most application software that is designed for the VGA or EGA video standard. Install the application as described in the application documentation. On system startup, the video circuitry automatically configures itself to 80-column text mode. Connect the monitor to the 15-pin video connector on the back of the computer. Refer to "Configuration Settings" in the "Installing Optional Hardware" section for video-related switch settings. SUPPORTED VIDEO MODES Mode 3 (80-column text) is the default video mode for the video circuitry for color monitors (Mode 7 for monochrome monitors). The video circuitry supports the following classes of video modes: * Other standard VGA modes, EGA modes, and MCGA modes--Provide resolutions of up to 640 x 480. * Super VGA modes--Provide even higher resolutions and the ability to display more colors simultaneously. Super VGA can also display text 132 columns wide and 25, 28, or 43 lines deep. * CGA, Hercules, and MDA modes--Required by applications designed to run under earlier video standards (CGA, Hercules, and MDA). For example, to run Hercules-compatible software and some CGA-compatible games, you must use a Hercules or CGA mode. When in a CGA mode, a Hercules, or an MDA mode, the video circuitry emulates the earlier video standard. USING VGAMODE.EXE The VGAMODE.EXE utility enables you to choose one of the video standards supported by the adapter. Choose from a menu or directly from the MS-DOS prompt line. To access the VGAMODE.EXE utility: 6. Turn on your computer. 7. Type: drive:\path\vgamode where drive: and path specify the drive and the directory containing VGAMODE.EXE. Then, press ENTER. 8. Use the up and down direction keys on the keyboard to select the desired video mode from the VGAMODE.EXE menu. Then, press ENTER. To exit, choose Exit to DOS and press ENTER. To bypass the menu, include the desired video option(s) when accessing VGAMODE.EXE. At the MS-DOS prompt or in a batch file, type the command in the form: drive:\path\vgamode [options] where options is one or more of the following video options. VGA--Selects VGA mode (the default configuration). CGA--Selects CGA mode (emulates the video capabilities of the IBM Color/Graphics Adapter). MDA--Emulates the Hercules Graphics Card with no graphics memory allocated (equivalent to IBM's text-only Monochrome Display Adapter). HERCO--Emulates the Hercules Graphics Card with one page of graphics memory allocated (equivalent to using the Hercules Graphics Card is HALF mode). HERC1--Emulates the Hercules Graphics Card with two pages of graphics memory allocated (equivalent to the Hercules Graphics Card in FULL mode). COLOR--Sets the video circuitry to color mapping as needed, supporting video modes that require color mapping. MONO--Sets the video circuitry to monochrome mapping as needed, supporting video modes that use monochrome mapping (such as monochrome text mode). 640--Sets 256-color, 640 x 480 graphics mode; use only with application programs designed to take advantage of Super VGA graphics. 800--Sets 16-color, 800 x 600 graphics mode; use only with application programs designed to take advantage of Super VGA graphics. This mode requires a multiple-frequency monitor. 1024--Sets 16-color, 1024 x 768 graphics mode; use only with application programs designed to take advantage of Super VGA graphics. This mode requires a multiple-frequency monitor. 56--Sets the video circuitry to 800 x 600 modes for 56 Hz. 60--Sets the video circuitry to 800 x 600 modes for 60 Hz. 72--Sets the video circuitry to 800 x 600 modes for 72 Hz. 200--Sets the video circuitry to display 200 scan lines. 350--Sets the video circuitry to display 350 scan lines. 400--Sets the video circuitry to display 400 scan lines. 400256--Sets the video circuitry to 640 x 400 resolution in 256 colors. 480256--Sets the video circuitry to 800 x 600 resolution in 256 colors. 600--Sets the video circuitry to 800 x 600 resolution in 16 colors. 768--Sets the video circuitry to 1024 x 768 resolution in 16 colors. 600256--Sets the video circuitry to 800 x 600 resolution in 256 colors. 13225--Sets 132-column, 25-line color text mode; use only with application programs designed to take advantage to Super VGA text capabilities. 13243 or 13244--Switches the video circuitry to 132-column, 43 or 44-line color text mode; use only with application programs designed to take advantage to Super VGA text capabilities. INTERLACE--Sets 1024 x 768 modes as interlaced. 60NON-INTERLACE--Sets 1024 x 768 modes as non-interlaced, 60 Hz. 70NON-INTERLACE--Sets 1024 x 768 modes as non-interlaced, 70 Hz. LOCK--Locks in the current video configuration as the new default configuration. This command can be used with another parameter to lock in that particular mode. For example, vgamode cga lock will enable the video circuitry to remain configured as a color/graphics adapter even after you press [CTRL] + [ALT] + [DEL]. Any specific video mode command will unlock the previous mode of the circuitry. IF YOU HAVE A MOUSE Changing videomodes is often simply a matter of running VGAMODE.EXE and choosing the desired setting. However, if your mouse driver is installed through the CONFIG.SYS file or if the mouse is controlled by a program such as MOUSE.COM, you might need to restart the computer after choosing a video mode.