[Coco] PBJ PC PAK - attn Gene Heskett

[Gene Heskett]

On Sunday 27 January 2008, Dave R in Illinois wrote:
>After further examination, it appears to be 34 pins, missing a few of
>course. Aligns perfect with my 3022 controller cable.
>
>I know either Gene or Bruce Calkins have the info I need, due to a post made
>in 2003.
>
>On a side note, why would it have a 34 pin connector for a parallel/serial
>port? Shame is a parallel port card, and not a controller.
>
My guess is that because many printers of the day used a 'Centronics' parport, 
which used more pins than a db25 supplied, and this was pinned out so that a 
34 pin CE connector, cable crimped to a properly oriented Centronics 
connector was used as the data cable.

I never had such a cable as the parport I used for a while came on the J&M-CP 
controller which had a 26 pin header, and someplace I have such a cable.  But 
I had to quit using it because the FCC required so much noise filtering that 
the < 2 microsecond active time was not sufficient to register with the 
printer.  So I had short lines full of gibberish on the paper after I 
converted to a coco3.  This particular PBJ item may, and probably did latch 
and handshake with the printer to make up for the short write times the coco 
in high speed mode, or a coco3, suffered from.  I considered building such a 
interface gismo for my J&M-CP, but printers were getting better & better, so 
I moved forward, or sideways as the case may be & hooked up a serial brother 
daisy wheel instead.

Personal opinion: PBJ built some pretty good stuff, and only fell over when 
casing the product in the blowmolded cream/white plastic in later years.  
That's pretty unforgivable, but an economic fact of life nonetheless.

Hopefully there is someone who does have such a cable, probably buried in an 
old printer box with the printer too, who can supply the pinouts and make it 
a usefull item again.  However, be aware that unless you've got the disk that 
came with it, you are going to have to write a driver.  I don't know if there 
was ever a driver for it in the os9 distro.

Driver wise, some of the routines are going to be very similar to the existing 
ports already in rsbasic, just with a different base address for the 6821, 
which needs a 4 address wide I/O space.

From scratch, I'd start with the data sheets for the 6821 and the centronics 
protocol.  Probably quicker and cleaner in the end.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
There's something the technicians need to learn from the artists.
If it isn't aesthetically pleasing, it's probably wrong.