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VGA MaxStation

commodorejohn

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So, some months ago, I was in an electronics surplus store and picked up what was obviously an X terminal - tiny metal slab with a VGA connector, serial & parallel, AT keyboard, and RJ45 "communication" port - named as in the thread title. I got it bare, without the external PSU that would've gone with it, and I've since been unable to determine just what the heck I'm supposed to feed this thing. It's a standard barrel jack, but there's no markings on the case or the PCB to give any clue as to what voltage/amperage or polarity it expects, and Google has been no help at all. Does anyone have any recollection of these things? Any idea what they want for juice?

To throw an extra mysterious wrinkle into this, when I popped open the case to get a look at the PCB, I found that, apart from the CPU, DART, and ROM, the only non-glue ICs on the board were an 8K SRAM and a W82C476 RAMDAC - but 8K isn't even remotely enough for a VGA screen, not even a monochrome one at VGA resolution! Am I missing something on how these things operated? Given this, my only guess would be some kind of insane networked-framebuffer scheme where the host would blast video data in on the fly, but there's no way this was even 100Mbps Ethernet, and 10Mbps isn't nearly fast enough to transfer 150KB at 60FPS, and there's no memory to buffer it for a slower refresh. What in the heck is going on here?
 
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commodorejohn

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Yeah - rather, it seemed to be an X-term when I was looking it over in the shop. According to someone on cctech, it's actually for running multiple terminals off an NT server, driven by a proprietary host card, so my crazy supposition as to how it works may actually be closer to the mark than I thought.

Of course, that means it's useless without the host, so I won't feel too bad about cannibalizing it for a project down the line.
 

shirsch

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Maxstation was designed to permit attachment of multiple dumb stations (monitor & PC keyboard) to a common host. There was driver support for them in several of the early PC Unix variants. Third-party versions of DRI Concurrent DOS (CCI for example) also used Maxstations. A business I ran in the early 90s had a 486 box with (4) of these attached to it. It does require the proprietary host adapter, so it obviously won't do you a lot of good.
 

commodorejohn

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Yeah, seems so. It's probably fated to end up as an easy way to get VGA timing signals and assorted interface stuff in a homebrew project down the line. Be easier if there were any service manuals/schematics anywhere, though :/
 
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