[Coco] Serial to usb printers

gene heskett gheskett at wdtv.com
Tue Jun 5 22:12:41 EDT 2012

On Tuesday, June 05, 2012 09:49:12 PM Luis Fernández did opine:

> Hi
> I do not know enough hardware to do this but I wonder?
> If the serial, the coco, has input and output, and 5V
>  And the usb I think, has something similar, but at high speed (tien
> 4-wire input and output voltage) Can anything be done or already done
> something?
If you are talking out driving a modern usb driven printer via the coco's 
bit banger, there are currently 2 ways I use often.  I did, before 
drivewire, run a couple scripts on this linux box that monitored the usb 
port created by connecting the bit banger port to a ser-usb adapter, 
waiting for something to be sent to /p on the coco/os9 system, writing it 
to a file, and when the data stopped, assumed EOF and sent it back to a 
printer plugged into the same hub as the ser-usb adapter was, using the 
cups 'lp' facility, which used ghostscript to convert the text into a 
rasterized image the printer understood.

However, since I have a 6309 in my coco3, and as nitros9 has never 
readjusted the /p timings such that "xmode /p bau=6" actually ran at 9600 
baud, which has to be pretty closely matched for the adapter to function.  
For my system, the default timing of 13 at bootup, giving around 12.5 to 13 
kilobaud, needed to be slowed by the utility that can adjust that to 
something in the 30 to 31 area.

Nowadays I use drivewire, which uses one of its 16 data channels as a 
printer port, doing the same thing except at 115 kilobaud.  The printer 
itself is a $120 B&W Brother HL2140 laser that runs at 21-22 pages a minute 
using the default font.  Fastest printer I've ever had on my coco, and 
beautiful output as lp can also specify any truetype font that exists on 
this machine.  Big, black fonts will of course use up an $85 toner 
cartridge faster though.

The older bash scripts are on my web page, but the drivewire solution is 
better, I don't have to fiddle with /p port speeds.

Cheers, Gene
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My web page: <http://coyoteden.dyndns-free.com:85/gene>
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