I'm trying to print to a QMS-PS 410 via the second serial port at 9600
baud. It appears that not everything sent arrives at the printer.
I've tried both XON and RTSCTS flow control. Running Kermit over the
same port to my Mac is successful. I've made sure my printcap is ok,
and even modified lpd to make sure IXON is set in the termios structure.
The cable is hand made, verified with a breakout box. The printer
does indeed send status (control T) when asked and runs fine in
interactive mode (the PostScript 'executive' command).
I've verified that the PostScript source is ok (a 17,061 byte
PostScript output from a groff'd man page, sent to my Mac via Kermit
and then prints ok via AppleTalk). I've even instrumented the serial
and n_tty drivers to printk when flow control is detected (this indeed
works). I've even set the printer to either XON or DTRDSR (via
appropriately connected cable for DTR->RTS, etc) flow control.
The printer appears to think it doesn't require flow control.
Setting the printer's serial buffer to 24K didn't help.
I should note that I was successful in using this same printer
from a PC532 running both Minix and NetBSD at 19200 and 9600 baud.
Has anyone noticed problems with the serial driver dropping output?
Craig Ruff NCAR cruff@ncar.ucar.edu
(303) 497-1211 P.O. Box 3000
Boulder, CO 80307