View Full Version : ITT XTRA XP XT/AT hybrid

September 7th, 2010, 01:49 AM
Hello everyone, I'm a newcomer to this forum.

I grew up in the 80's with a PC clone Victor Vicki 8088@7.16MHz (=1.5 times 4.77MHz) 512kB RAM, 2 360kB 5 1/4" floppies, Hercules graphics with green monochrome display. Over time I talked my parents into upgrade it with 10MB hard card and a microsoft bus mouse, the mobo had a socket for the bus mouse IC. I had this computer for about 5 years and then got a 486DX/4MB RAM/340MB HD which I eventually upgraded to a 486DX4/100MHz and the list goes on...

I recently felt the urge to have a trip of nostalgia so I got an ITT XTRA XP XT/AT hybrid almost for free. It's quite interesting hardware-wise, it has 8-bit bus but with a 286 processor at 6MHz, memory with 0 waitstate and a 20MB MFM HD. The graphics card, which I guess is not the original one, is an 8-bit Video7 VGA card that also supports EGA/CGA/MDA. I don't know about RAM yet, possibly 1MB. I also got lots of floppies with interesting programs on them, games and development tools.

I managed to find specs online for the graphics card and set the jumpers for VGA output (was EGA when I got it) and I hooked it up to my monitor and it works. My problem now is that I don't have a PC/XT keyboard and the bios accordingly displays keyboard error and stops there. The computer has a 5-pin DIN connector. I believe the computer expects a XT compatible keyboard, I would be incredibly lucky if there was a jumper setting on mobo for using an AT keyboard, but I don't think so.

Does anyone have any information about this computer, in particular mobo jumper settings? There are quite a lot jumpers and dip switches on the mobo. This is a long shot; is there a way to fool the bios to pass the keyboard test by maybe shorting pins on the connector?

September 7th, 2010, 02:26 AM
Welcome! I think I saw that ITT XTRA on the Tradera auction site, but decided I have too many 8088 clones as it is.

I can't help you with the DIP switches, but people on this forum have recently developed an AT/XT keyboard adapter (http://www.vintage-computer.com/vcforum/showthread.php?15907-AT-to-XT-Keyboard-Converter) that will take a PS/2 keyboard input as well. It comes as DIY so you may need to find components and solder it up yourself, but in case you are unable to find a true XT keyboard, it is the next best thing.

Actually I own a Vicki 8088 and have been wondering about the bus mouse IC. The manual only mentions you should insert "the" chip, but not what "the" chip consists of. Do you remember? Is it a ROM/EPROM, a custom chip or something else? I've asked owners of other Victor's which may be similar but didn't get any affirmative answer.

September 7th, 2010, 03:04 AM
Thanks Anders, that's correct, I bought the item from Tradera auction site, it is not very often you see any PC/XT's for sale these days in sweden.

I have read about both the XT-IDE interface and the AT2XT keyboard converter and I'm impressed by the collective skills in this forum. Unfortunately I'm not into soldering stuff myself but I will consider it.

About the bus mouse, it was a mouse interface developed and sold by microsoft. It's main advantage over serial mouse was that it used interrupts instead of polling, which used CPU resources. The bus mouse was basically a chip called Microsoft Inport together with a physical connector on an ISA card. On some PC clones the connector was implemented directly on the mobo with a socket for the Inport chip. In those days you could buy a Microsoft bus mouse bundled with the chip. When the PS/2 was launched 1987 and introduced PS/2 mouse interface that gradually became the standard way to connect a mouse.

September 7th, 2010, 05:14 AM
During internet search, I ran across this article (http://www.atarimagazines.com/creative/v10n12/71_ITT_Xtra_an_IBM_PC_compa.php) about ITT XTRA, the predecessor to my computer with 8088 cpu. The article says "The Xtra supports a mouse, which plugs into the keyboard port. Both mouse and keyboard can be used at the same time." Very interesting. I also found this ad (http://books.google.se/books?id=pS4EAAAAMBAJ&lpg=PA24&ots=f1KcUehvDM&dq=%22itt%20xtra%22%20%22interface%20box%22&pg=PA24#v=onepage&q&f=false), it seems they had a proprietary mouse interface through the keyboard connector. I find it fascinating to see in hindsight the PC clone manufacturers attempts to get a competitive edge against each other.