PRINTER OUTPUT PROBLEM

[WOLF%MCL.SAINET.MFENET at nmfecc.llnl.gov]

My system is a Convex C1-XP (now called a C120). I have a printer problem.
I have a Printronix P-300.  When I run it at 9600 baud, files come out
with pages missing (prints page 1, 30, 61, etc.).  At 4800 baud, it
prints pages 1, 17, 37, 44, etc.).  At 2400 baud, it prints pages 1,
4, 9, 15, etc.  These page numbers are approx., but the pattern is 
clear.  I have placed a data analyzer in the circuit, and the RS232 board
is sending the XON and XOFF characters correctly.  Also, I have placed
a microcomputer as the source to the printer, and there are no pages missing
in the printout.  Therefore, I have to assume that there is a software
problem.  (I also changed ports, so I don't think it is a port problem.)
The port is configured for software flow control (XON XOFF).  The 
printer does not have a controller, it is running from a terminal port.
I believe I need a correct filter for the Printronix. The printer
works correctly at 1200 baud, but this is not satisfactory. Help! 
I have taken extra care to make sure everything is correctly changed 
with the /etc/ttys file and with /etc/printcap.  Convex Unix is 4.2 
BSD with a few additions.  Would somebody please send me the filter or 
point me in the right direction.  My address is

WOLF%MCL3.SAINET at NMFECC.ARPA

                                Thanks,
                                        Andy Wolf

P.S. While I've got your attention, I have another brief question.  I
don't have a Usenet feed yet, but is there a way I can get to the 
chess newsgroup?  I access ARPAnet and/or MFEnet.  Thanks again.