M200 interfacing

From: Ben Franchuk <bfranchuk_at_jetnet.ab.ca>
Date: Sun Dec 29 15:39:01 2002

Fred Cisin (XenoSoft) wrote:
> On Sun, 29 Dec 2002, Sellam Ismail wrote:
>
>>And I forgot to mention the really funky codes that combine two of the 12,
>>11, 0 zones and multiple rows to form special characters (like 12-0-1-8-9
>>for NUL in standard IBM EBCDIC).
>
>
> And don't forget the silliness of punching graphic images on cards. I was
> showing punch cards to my OS class, including portapunch (right after a
> certain Florida election). I wanted to show them some of the variations,
> such as round-hole and other sizes (there are some great stories about
> some of those!), and the only example of the half sized card that I had
> was punched with holes making a picture of a hand giving the finger.

> Why not just read two columns, each of which is twelve bits, pass that as
> three bytes of raw binary, and then decode in the host machine?

I would read all 80 columns 16 bits each.
Remember often a blank column could be read
as a leading zero. One place to look for card
to ascii? encoding is old data books on mask
programable roms as that was a common use for
them.
Ben.
Received on Sun Dec 29 2002 - 15:39:01 GMT