[Coco] Telepak RS232 Pak
operator at coco3.com
Thu Feb 12 18:21:25 EST 2009
At 11:49 AM 1/17/2009, you wrote:
>So does mine, I made one of them out of a modem pack too, but it
>only works in
>an MPI because those level translator chips need its plus and minus 12 volts,
>which the coco 3 does not supply, and which the older coco's only supplied
>very marginally, around +-9 volts IIRC. That is enough to make it work 99.9%
>of the time, but leaves precious little over drive for noise margins and poor
>or long cabling.
>For all new designs, investigate the MAX-232 line of chips for that function,
>which contain their own charge pump level translators that are probably 500%
>more efficient than the Aztec mini-switcher in the RS-232 Deluxe pack ever
>thought of being. That puppy ran HOT! Or did in the 2 I have. Neither have
>survived the ravages of age and 24/7 uptimes at the Heskett ranchette.
Gene, I was reading back on our discussion about the 6551 paks
running or not running on a CoCo 3.
Reading up on the MAX232 I see it generates (from a single 5v supply)
+-7.5v, not +-12v signals.
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