USR quad modems... (ontopic - really!)
ard at p850ug1.demon.co.uk
Wed Aug 16 17:16:18 CDT 2006
> So, I have an older USR Total Control system with quad V.34 modems on each
> card, and prolly 12 cards in the system.
> I was curious as to just what makes this sucker tick, so I pulled a card &
> started looking at chip numbers...
> Each "modem section" has:
> an Intel 80C186 (same chip as in the Tandy 2000) - except they're rated for
> a TI/USR DSP chip, which is prolly useless outside of the intended use
Somewhere I have ao old 1200 baud modem which uses an 8088 as the DSP
(!). And I've heard of modems which used PICs as digital filters.
Drifting even further away, I have an X terminal which uses an 80188 for
I/O. The X server runs on a TMS34010 video processor (!).
> 2 each 32Kx8 static ram chips,
> 4 each 128Kx8 static ram chips
> and lots of other 8/16-bit 74-series buffer chips & whanot.
> So, *if* I can get a Dynamic-RAM -> Static RAM converter board designed for
> the CoCo, I could upgrade 4 CoCo3s to 512K with each modem board.
Hmm.. Both the SAM (CoCo 1 and 2) and GIME (CoCo 3) chips are pretty much
designed to use DRAM. They output the multiplexed addresses and all the
right timing signals. Surely 41256 DRAMs are not that rare yet? It would
be a lot easier to stick 16 of those into a CoCo 3 to get it up to 512K.
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