bill@fedeva.UUCP (Bill Daniels) (07/21/89)
We have a Printronix P300 serial printer connected to an Ultrix MicroVAX
3800 via a CXY08 8-line RS232 controller. Which of the RS232 signals
is monitored by the lpr print spooler to recognize that the printer is
off-line? The printer can be configured to drop either CTS or DTR.
The printer can also send an XOFF (dc1/^S) but this seems to be ineffective
if the spooler is not in active communications with the printer; I guess
nothing has the port open for read at the time in order to pick up the
software flow control character.
We are really trying to avoid a situation in which the printer is placed
offline while the spooler is inactive and a print job queued while the printer
is still offline. In this case the spooler goes merrily about its way of
dumping a bunch of stuff to the printer which isn't expecting it, doesn't
know that it has started, and consequently loses the job.
We also have available DECserver 200/MC ports across LAT if that will help
with a solution.
--
bill daniels
federal express, memphis, tn
{hplabs!csun,mit-eddie!premise}!fedeva!wrd3156grr@cbmvax.UUCP (George Robbins) (07/22/89)
In article <463@fedeva.UUCP> bill@fedeva.UUCP (Bill Daniels) writes: > We have a Printronix P300 serial printer connected to an Ultrix MicroVAX > 3800 via a CXY08 8-line RS232 controller. Which of the RS232 signals > is monitored by the lpr print spooler to recognize that the printer is > off-line? The printer can be configured to drop either CTS or DTR. > The printer can also send an XOFF (dc1/^S) but this seems to be ineffective > if the spooler is not in active communications with the printer; I guess > nothing has the port open for read at the time in order to pick up the > software flow control character. "offline" is relative in this case. If you have the serial port configured for modem control (flags in config file and possible mode bits in the /etc/printcap file) then you should be able to use the "drop CTS" option to effect a form of hardware flow control. You might also be able to cross-wire the printers "DTR" line to your "DSR" and/or "CD" line which would make attempts to "open" the printer hang/fail while it is offline. None of this is really printer specific, it's just taking advangage of some of the stuff supported by (some of) the serial drivers/interfaces. If you enable "modem control", you generally need to connect DSR, CD, and possible CTS to some signals to make sure they are "asserted" as if there were really a modem attached. -- George Robbins - now working for, uucp: {uunet|pyramid|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@uunet.uu.net Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)