Tony's kit, was: Re: USB Stuff
ard at p850ug1.demon.co.uk
Tue Oct 4 15:14:57 CDT 2005
> Tony Duell wrote:
> > Actually it doesn't. I am looking at a monochrome green screen at the
> > moment. OK, I do have colour monitors around here....
> I know I've asked this before but I don't recall the answer. What
> exactly *do* you use to connect to the Internet?
I am sure I described it a couple of weeks ago here, and I've not
downgraded  since then
 That is, to sowmthing without schematics.
OK, here you are again :
A much-hacked IBM PC/AT (8MHz system board). The mainboard has a 486
kludgeboard in the 80286 socket. I've added a couple of EPROMs and a bit of
logic to overlay the last 8K of the bios, so I could modify the hard disk
Thers's 512K on the mainabord. Abother I/O card adds the 128K to bring it
up to 640K + anothet 1.5M extended memory + 2 serial ports (16550s, of
course, I want to give this processor all the help it can get) and a
parallel port. Another expansion board started off life as an IBM 128K
card. I figured out it could be populated with 2 rows of 256K bit DRAMs,
and a bit of extra logic, and turned it into a 1M card. Although all the
traces for this were there, etched on the board, I can't find any mention
of this in the TechRef. And another board adds a further 2M of RAM.
There's an original IBM MDA board linked to a 5151 greenscreen monitor.
And a Colorgraph+ (Enhanced CGA card, with enough RAM for 640*200 in 8
colours, pity nothing supports it). That's linked to an NEC monitor that
was used with an Apple ][, which I modifed to add the intensity line.
The disk controller is an early IDE card, a few TTL parts, a couple of
PALs and a floppy controller chip. I added a daughterboard containing a
couple more TTL chips to flash the frontpanel drive LED when the hard
disk was accessed. It's linked to the original IBM 1.2M drive and a Teac
1.44m 3.5" drive. And to a 1.3G IDE winchester.
TO actually connect to the phoneline, I've got an old USR Sportster 14K4
modem. That, and the hard drive, are the only parts of the system I don't
have full schemaitcs for.
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