From: isc10192@nusunix1.nus.sg (KOH KHANG WEE)
Subject: Re: 16550 Uart questions..
Organization: National University of Singapore
X-Newsreader: TIN [version 1.1 PL6]
Distribution: usa
Date: Sat, 26 Dec 1992 02:05:19 GMT

I/We are Gaia (gaia@carson.u.washington.edu) wrote:
: I just started reading this news group, and have read all I can on this
: particular subject here, but didn't seem to get an answer to my particular
: questions, so I guess I have to ask anyway..
: 
: I just got a SupraFAXmodem v.32bis, my are the threads here vicious on
: them, but so far I haven't had any problems at all, I do seem to have the
: 1.200-H revision roms.  Are these the most recent?? Anyway, I had to put
: the com software down to 19,200 since the 8250/16450 uart just spits at
: 38,4 or 57,6.  Here is my question..

Well congrats, i too am a satisfied supra owner. And yes, i changed the
i/o card because the 16450 sucks at high speed. And yes 1.2H is new...
they have got a 1.2J which is the same but for an added feature - caller
id. caller id works only if ur phone company supports it.

: 
: I have a generic 8 bit multi-io card, and the manual that came with it,
: actually better than most I have seen, it actually gives details..  It
: says to enable the second serial port I have to insert the following Ic's:
: 1488,1489,and 16450 (I assume this is the uart), I have seen the card, it
: does have both serial ports installed, and the base seems to be setup the
: same way.  In order to get the advantage of the 16550, can I just unplug
: the 8250/16450 and plug in a 16550??  Do the other 2 chips (small like
: drams) need to be replaced, if so with what??  Does it need to be a 16bit
: card??  And finally where can I get a genuine National Semiconductor
: 16550AFN if all this is possible, for a decent price.  
:
I think that if the secondary UART is not soldered in, the chip can be
unplugged and replaced straitaway with a 16550AFN, this was told to me
by some shops. But too bad, mine was soldered on, so i had to get a new
i/o card. I dun think the other 2 support chips should be replaced, they
are quite generic to all i/o cards. I dunno where u can get a GENUINE NS
16550AFN, cos i live in Singapore and we only got taiwan 16550AFNs, they
are quite cheap here (about US$7) FYI. Also do not get a 16550A, it's
buggy.
 
: Right now I am getting close to 1800 cps in procomm for windows, but I
: wouldn't mind to see if I can get more, but also I would just like to run
: at recommended rates, you know 57,6 for 14.4 compressed data, and all
: that..  That is with Zmodem by the way.  

1800 cps, i suppose u use Ymodem-g, ok this protocol has no built in
error correction, it assumes the modem u have has error correction
(highly unsafe for unclean lines when modems cannot connect at error
correction mode) with the 16550 UART i got a cps rate of close to 1950
with ymodem-g. Zmodem is better, such that it has built in error
correction, transfer rate is of course slower, but worth it most of the
time, average transfer before the 16550 was 1550cps, after installing
the 16550, it was 1650cps. Hope this helps.
: 
: Funny, my supra connects to my university dial-in, but apparently I know
: someone with a Intel 14.4/fax that can't connect above 9600 while I nailed
: 14.4 on my first try, I just am one of the lucky ones I guess..
:
dun think that's wierd, your school's modems are probably not configured
properly (often the cause of 99.9% of modem problems) and if u use
procomm for windows, ur supra has the best configuration u can churn out
as procomm provides the config 4 u. That's why u have such good
performance from ur supra.... just like me...

Hope what i've said helps....email me if u need anymore help. 

: Any info appreciated..
: Gaia@carson.u.washington.edu

--
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
	Jerry Koh 	a.k.a. 		FLAT^^TOP
		 isc10192@nusunix.nus.sg
	     national university of singapore
	     D.     I. 	    S.	    C.	   S.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Newsgroups: comp.dcom.modems