[CQ-Contest] Expanding Comm Ports

[Michael A. McCarthy]

k4oj wrote:
> 

> It seems that the cards that are out there boil down to ones using a 16C650
> UART (whatever that is) or a 16C550 UART - I gather the 650's are better
> since they cost more...I want to  get a card which will add ports for
> contesting applications and since the 650 is almost twice as much mobney as
> the 550 I don't know if this is something I need to adress or not - mebbe
> for the kind of stuff I am doing the 550 is good enough and I can add more
> ports for less....

   You won't need the 16650 for anything under 115K bps.  The 16650 is good
for ISDN connections where the port rate is set to 230K bps.  With most ham
gear,
you are hard pressed to find anything that runs faster than 9.6K.  Also, the
16650 is not directly supported by most software and needs a special driver to
enable the extended buffer and use the ultra high speeds.
> 
> I currently have a 486/MX Dell optiplex machine and am using Windows 95 on
> it - although I use the contesting software straight from the C: prompt,
> not through a Win95 window.
> 
> Also, I only have one card in the machine - a sound card, so I could have
> room for more cards....since adding four ports seems really cool (I would
> go from two to six) is it better to have two cards with two on each or to
> have a single card with four on it (the money isn't much different but the
> angle of possibly having a failure on one card and still having the other
> going interests me....as always a pessimist!

   Find an SIIG, Inc. 4 port Hi-IRQ, Hi-Speed (16550) serial card.  The newer
ones are addressable for COM1 through COM8 and all possible IRQ's.  They
come with chips for only two ports, so you will need an expansion kit to
get the other 2 chips and cables.  They are available from Comp-USA and
Computer City.
   I have two of these cards.  The older ones only addressed COM1-4.  The
latest ones do COM1-8, so they can be added to a system that already has
two ports for a total of six.  Just be sure to select unused IRQ's for each
port.
> 
> ...should I get the 650's or will the 550's do it for me?

   Again, you don't need 650's for anything less than 115K bps...

73,
Mike W1NR
-- 
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Michael A. McCarthy, President
Everest Engineering Corporation, Consultants
4 Barnes Circle, Marlborough, MA 01752
(508) 460-6737, FAX (508) 460-7951
mailto:w1nr at eecorp.com
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