Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!swrinde!ucsd!ucsdhub!hp-sdd!hp-pcd!hplsla!hpubvwa!apl-em!dunlap
From: dunlap@apl-em.UUCP (John Dunlap)
Newsgroups: comp.sys.hp
Subject: Re: 2 serial port questions (HP 9000/835 HP-UX)
Message-ID: <630021@apl-em.UUCP>
Date: 16 Feb 90 16:50:08 GMT
References: <4685@aplcen.apl.jhu.edu>
Organization: Applied Physics Lab, UW, Seattle WA
Lines: 22

>> Are the serial ports on my 9000/835S really able to communicate at 19.2K?
>> Can I get any kind of xon/xoff type support?

We have XON/XOFF trouble with the 6 port mux on the 9000/550.  As I
understand it, this card for the 800 and 500 series is nearly the same.
Upon receipt of an XOFF character, the 6 port mux (27140) takes longer
than the 8 port mux (27130) to stop its output stream.  This has caused
data overflow on some of our terminals (Z-19 with Northwest Digital
graphics boards).  The terminals evidently have almost no buffer space
left when they send the XOFF to the mux.  This problem occurs at 9600
bps with the 6 port mux but not with the 8 port mux.

We also experienced data overruns when connecting a 6 port mux with
an 8 port mux using CU at 19200 bps, but it was OK at 9600.

We have no problem running a LaserWriter NTX-II on an 8 port mux
at 19,200 bps using XON/XOFF flow control.

John Dunlap				Applied Physics Laboratory
hpfcse!hpubvwa!apl-em!dunlap		University of Washington
dunlap@apl-em.apl.washington.edu	1013 NE 40th St
(206) 543-7207 or 543-1300		Seattle WA   98105