[Coco] serial cable tricks for drivewire?

Bob Devries devries.bob at gmail.com
Thu Mar 1 16:42:22 EST 2012


Hi again, Robert.

I found this on a website (see below for URL):

Reduce the cable capacitance as far as possible. RS232 does not carry a lot 
of current so anything larger than 0.02mm2 (because anything smaller will 
break!) is a waste of copper. Reducing the outer area of copper will 
automatically reduce the capacitance of the cable, and significantly too. A 
favourite cable for wiring fixed installations is indoor telephone cable 
(ITC).
The second (and more important factor) is that every signal uses a twisted 
pair with one leg being a ground return, regardless of what the signal is 
(and this includes DCD, RI, etc.). Again, the favoured ITC is already in 
twisted pairs.

http://www.marcspages.co.uk/tech/long232.htm

Regards, Bob Devries
27º10'26"S, 151º16'30"E


----- Original Message ----- 
From: "Robert Hermanek" <rhermanek at centurytel.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Friday, March 02, 2012 6:59 AM
Subject: [Coco] serial cable tricks for drivewire?


>I have a number of coco's connected to a single server via serial cables 
>and drivewire.  The drivewire server in this case is an application I wrote 
>myself to be compatible with DW3 HDB-DOS, and since it allows multiple 
>coco's to access the same DSK images simultaneously, it makes it easy to 
>swap files between coco's, i.e. build program in Edtasm on one machine, 
>swivel chair and execute it on another...
>
> Sounds great, but the downside to my setup is that the server is located 
> far away from some of my coco's, and in one case I end up with a serial 
> cable that is 50+ feet long.  This connection is not reliable at 115k 
> baud.
>
> I'm guessing 50+ feet (with no hardware flow control) is well beyond the 
> official maximum length of a serial cable.  Does anyone know of any tricks 
> to allow longer serial cable connections to function? i.e., better 
> connectors, different cable, things like that?
>
> -Robert Hermanek
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco 




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