Linux-Hams archive - July 1997: Re: KPC3+ problem and serial chip
Re: KPC3+ problem and serial chip
Karl Larsen (ydpd@bka.gv.at)
Thu, 03 Jul 1997 04:58:41 -0700
Albert Woodhull wrote:
>
> A while back I asked for help on a problem I have had with the KPC3-Plus
> TNC (but not the older KPC3) in KISS mode. I still haven't solved that
> one, nor has Kantronics answered my query to them, but I received a reply
> that has me wondering about another possible problem.
>
> One writer suggested I would have a problem with either Windows or Linux
> and a KISS TNC if I do not have a 16550AF serial interface chip. I have
> noticed on my listen screen that sometimes I get packets that aare missing
> a character or two. The characters are not garbage, they seem to have
> dropped out. This would be consistent with a serial buffer problem.
> This is different from the problem I had earlier, although I suppose it
> could be related -- I suppose there are bytes that could cause something
> that looks like a wild buffer overrun problem if they dropped out.
>
> My Linux dmesg and an old Microsoft MSD tell me only that I have a 16550A.
> Question number one is, can someone confirm that an ordinary 16550A is not
> good enough? Question number 2 is, can the Linux kernel detect the difference
> between the A and the AF (I am now using a 2.0.30 kernel)? Question 3 is,
> is there anything I can tweak in the kernel code to compensate?
>
> The computer in question is a Compaq Armada 1120. It is a reasonably current
> model (purchased Jan 97). I thought the serial port chip question was one
> that had been resolved quite a while ago, should I be concerned with such
> a new computer? It is a laptop, and I am not sure how easy it would be to
> look inside it, nor am I hopeful that I would find a socketed and replaceable
> serial chip if I did so.
Al, it does not matter which chip you have in your computer's serial
card. There are none so bad that you loose bits at 1200 or even 9600
baud. In my Linux system I'm using a $12 multifunction card that has the
slow unbuffered serial hardware. I have had no problems. But when I try
to run my 28,800 telephone modem I do get into trouble.
Odd, but win-95 has solved the problem using a software approach. I would
like to port that software to Linux. For sure Bill Gates would charge a
bundle...:-)
>
> 73, Al N1AW / YN1ASW
>
> --------------------------------------------------------
> Albert S. Woodhull
> loe@ilstu.edu
> adstbyu@roskapostia.tunk.net
> pvbnumjb.jipbcnemra@scottlabel.com (solamente dentro de la UNAN)
> txec@brutele.be
--
73, de Karl aka k5di
Karl F. Larsen Box 74, Mesilla Park, NM 88047 (505) 524-3303
mwiq.acqk@katch.ne.jp terhi.victor@logonet.com