Printronix P300 on RS/6000 320

[Mike Stefanik/78125]

Hopefully someone out there could give me a hand with a printer that is
giving me a major headache.  A client of ours has an old Printronix P300
serial line printer which they want connected to their RS/6000 320.  The
OS is running with the 3002 updates, and the printer port is configured as
a 9600 bps 8/2/N "other serial printer".

We have not been able to get the printer to work using IBM "standard"
RS232 cabling (interposer and all).  I flew up to the site and brought my
trusty "paperclip with lights" (ie: breakout box) and discovered something
strange: the printer worked swimmingly when I jumpered DSR to RTS, forcing
RTS high.  After playing with it for a while, it seemed that RTS needed
to be forced high for the printer to remain conscious.  Just for giggles,
we built a cable like this, and the printer worked *until* the system was
rebooted; then terminal brain-death (on the part of the printer).

We talked to Printonix, and they said that the P300 knew nothing about
XON/XOFF (so we changed that to "no" via SMIT) and used DTR.  Other than
that, they couldn't give us any useful advice.  We have three other printers
on the same mux, and all of them are working just fine (they're HP
Laserjet III's).

Question: has anyone out there tried to hook up a Printronix P300 to an
RS/6000?  To any type of UNIX box?  Thanks in advance for any and all
suggestions.

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Michael Stefanik, Systems Engineer (JOAT), Briareus Corporation
UUCP: ...!uunet!bria!mike
"If it was hard to code, it should be harder to use!"