>>> Indeed. A couple of years ago, I asked to mazak for the replacement for the >>> standar CRT monitor. They quoted me US 5000 more or less, for the entire >>> unit. By that time, we were using the lathe with an old CGA monitor, >>> because the frequency is the same. I bought an adaptation board from CGA to >>> VGA so now I can use any monitor. But yes, they're thiefs!
I'd like to see how a VGA output was adapted to a CGA monitor. VGA uses three analog frequency outputs, each with its own ground, and two sync outputs, which in some implementations are tied together as composite sync. Adapting a TTL monitor to a VGA output would require a complex and expensive box with ADCs and at best you'd get 64 colors. I'd expect such a device to cost as much as a monitor so why bother? Since bare bones VGA only needs 8 wires, some monitors made in the early years of VGA just used a single 9 pin input and had switches to change among mono/Hercules, CGA, EGA and VGA. I had one, must have been NEC's very first model of Multisync(TM) because that's all it had on it, no model number at all. Even had a cooling fan. IIRC it's top VGA resolution was the Macintosh one that's a bit over 800x600. Mono/Hercules, CGA and EGA use TTL signaling with discrete levels, various combinations of which are used as coding to make the monitor produce the various colors from a limited palette. A CGA monitor could be connected to an EGA video output and in most cases it would work, even with the low resolution 320x200 16 color EGA mode that CGA doesn't have. But a CGA monitor could not work with the high resolution 640x350 EGA mode. Some non IBM/PC micro computers could be modified to drive a CGA monitor in a way to display higher resolution and/or more than 16 colors, but it skates right on the edge of the monitor's capabilities and some monitors just wouldn't handle it, especially if designed to be very precise on the TTL signal transitions. Stock EGA could display the full 64 color palette by using interlace and fast switching hacks similar to how Amiga computers could come close to displaying their full 4096 colors but nobody ever used the EGA hack on anything but a "See? 64 colors!" demo due to horrible flicker. There were a number of incompatible "Super EGA" modes made by various video hardware manufacturers, supporting resolutions up to 800x600. The trick was finding a monitor capable of not just the higher scan frequency required but the *exact* frequency a specific "SEGA" video board required. I had one of the earliest PC motherboards with multiple integrated peripherals, made by Western Digital. It had serial, parallel, floppy, IDE and some odd "SEGA" video with resolutions up to 800x600. Every built in peripheral had a jumper to disable it *except* the video, and it was not configurable to be able to run dual video with any other card in an ISA slot. Worked just fine with a standard EGA monitor. IIRC it was a 80286 LCC package CPU. Then IBM released VGA and nobody cared anymore about enhancements to obsolete TTL video systems. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ------------------------------------------------------------------------------ Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
