SWTPC 6800

Fred Cisin cisin at xenosoft.com
Fri Aug 5 10:51:36 CDT 2016

> but as with all problem solving, Conan Doyle had it right when he said 
> "after eliminating the impossible, whatever is left, however improbable, 
> must be the solution"

That quote is often horribly abused.  Diagnosis by elimination 
is inherently faulty.  Beginners, and "experts", will often 
use it to justify ridiculous premises, "because I eliminated everything 
else", while not having truly eliminated some of the most basic 
possibilities.  "It must be the carburetor, because everything else is 
new" usually meant that they had not gapped the points properly, or had 
the wrong firing order.

37? years ago, it took me 3 weeks to get ink on paper with a serial 
printing terminal and a TRS80, because I made stupid assumptions because I 
thought that I had eliminated . . .
and didn't even realize that there was a bad connection between the serial 
interface and the rest of the Expansion Interface.

Why do you think that you have the right baud rate?
It might be 9600, but if it was expecting a printing terminal, then it 
might be 300, 150, 134.5, 110, 75

In spite of "standardization" (everybody has a unique one of their own), 
sometimes you run into some handshaking using signals besides DSR, DTR, 
RTS, CTS.     Such as CD (8), CD2 (12)!, RI(22)
"misuse of the standard"?  absolutely.
(using db25 pinout - BTW, a DE9 is not a DB9.  A real DB9 consists of a DB 
shell with 1 thru 8 and 20)

It can be frustrating.  There is at least one documented fatality from the 
frustration of serial cabling.   Guy took a printer and computer to store 
to get it cabled; after 6 weeks without success, he shot the tech.  Joe 
Campbell was sure that was an urban legend, so he tracked down the case, 
and mentioned it in one of his books.

I don't intend to ever do it again; I'm getting rid of my ARC Data Tek 
9600 DTS-1.

Grumpy Ol' Fred     		cisin at xenosoft.com

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