Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!lll-winken!unixhub!linac!att!news.cs.indiana.edu!maytag!xenitec!zswamp!root
From: root@zswamp.fidonet.org (Geoffrey Welsh)
Newsgroups: comp.dcom.modems
Subject: AT I/O card with 16550, available
Message-ID: <7127.27F41B8C@zswamp.fidonet.org>
Date: 29 Mar 91 17:55:39 GMT
Organization: Izot's Swamp BBS - Kitchener, Ontario
Lines: 55

Barton F. Bruce (bruce@camb.com ) wrote:

 >The EVEREX 'Magic I/O card', their # EVO-00-170-A1 sadly
 >has a 16450 chip, and that is what most distributors and 
 >hence dealers are stocking. There IS another model
 >available from EVEREX that has a 16550 that is really the
 >same card, different UART. It is the # EVO-00-170-A3. That
 >is NOT a National chip in there but a Mylex (sp?) (MX with
 >a slashed X logo), [...]

 >If you know any PROVEABLE reason that THAT 16550 they are
 >using fails where the National one doesn't, I want to know,
 >and I will call the product manager or mail you his name
 >and number if you prefer. He is convinced it is ok.

   YOU DON'T WANT THAT CHIP!

   Recently I ordered some NS16550AFNs from a nearby distributor and, after a 
significant delay, they said that National parts were not available but that 
these MX chips were.  The salescritter assured me that they were 100% 
compatible so, after extracting a promise of full credit towards National 
chips if I was not satisfied, I ordered some.

   The chip was a disaster.  I've used both -AN and -AFN chips with no 
troubles before, but these MX chips were impossible to get along with.  They 
didn't lose characters, I'll give them that much credit... but it appeared (I 
stress the word "appeared", because I didn't hang on to the chips long enough 
to do a detailed analysis of them) as if the MX 16550 chips simply failed to 
generate interrupt requests every now and then, effectively locking up the 
serial port.  I was worse off with the MX chip - which locked up at any time - 
than with a regular 16450 or 8250, which only lost characters while I was 
multitasking heavily on my machine (and would be able to do something if a 
nonrecoverable error cropped up, not that it ever did)

   Immediately I set about returning the MX chips.  Unfortunately, the person 
who made me the promise seemed to be perpetually 'out' for nearly a week, 
after which I learned that he was no longer with the company.  A short chat 
with a techie at that company revealed that many customers had complained 
about the MX chip.

   I bought NS16550AFNs from another source and plugged them in where the MX 
had been.  No problems.  At all.

   When buying 16550s, DON'T SETTLE FOR ANYTHING LESS THAN GENUINE NATIONAL 
PARTS.
 

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