Chris Bartram writes:

> > The bottom line of all of this is: with an external JetDirect card, you
>  > put the cheapest RadioShack dot matrix printer on your network and have
>  > HP3000 print it now, so long as it has a parallel port on it (and for
most
>  > cheap printers, that's all they have).
>
>  I don't believe that's entirely true (at least not from personal experience
>  and extended conversations with the HPRC)...
>
>  I've worked with a couple printers that would NOT work with HP network
>  printing.. Including a brand new Epson high-speed dot matrix printer.
> Despite
>  extended "tweaking" it would not talk (used an external Jetdirect hooked up
>  to it's parallel port).
>
>  According to the HPRC, to function with network printing, the printer has
to
>  have some minimal knowledge of either PCL or PJL (I forget which, but I
>  think it was the printer-control-language vs printer-job-language). This
>  dependency is hard-coded into the spooler subsystem.

To test Chris's response to my previous contention, I took an old Radio Shack
Tandy DMP 204 24-pin dot matrix printer out of the closet, disconnected the
parallel port end of the JetDirect EX Plus that services our HP755CM DesignJet
large-format printer and connected it the Tandy dot matrix printer.

The results were halfway in between working and not working. The little Tandy
printer is just smart enough to get itself in trouble. It listens to the
Esc-1234X PCL sequence that's sent out right at the beginning of the document
and gets itself confused. However, if I then turn the printer offline and back
online, the remainder of the ASCII document prints just fine.

A bit of a pain, to be sure, especially given that I have PJL_SUPPORTED as
FALSE in our NPCONFIG file. While the ideal situation would be for the HP3000
spooler not to be sending this prefix material at all if PJL support is turned
off, a secondary cure would be for me to find some way to suppress the Tandy
printer from responding to escape sequences (i.e., be programmed to be a
*really* dumb printer).

Our NPCONFIG file (simple as the day is long):

=======================================

global (message_interval = 60
        banner_trailer = FALSE
        pjl_supported = FALSE
        jam_recovery = FALSE)

6      (network_address = 192.168.1.100)

300    (network_address = 192.168.1.100
        pjl_supported = TRUE)

301    (network_address = 192.168.1.110)

302    (network_address = 192.168.1.120)

303    (network_address = 192.168.1.130)

304    (network_address = 192.168.1.140)

305    (network_address = 192.168.1.150)

=======================================

By luck it appears, all of the other printers that we've hooked up to the
HP3000 (Tektronix color laser, Apple LaserWriters, Seiko Colorpoint) don't
react to the prefix string that MPE is sending out and work just fine.

Thinking about it now, the reason that for our success with these other
printers seems clear: we tend to exclusively use PostScript as our HP3000
printing language here -- and the PostScript interpreters in these various
printers have all been programmed to ignore any PCL-like text that they see
prior to a legitimate start of a PostScript command file. When we do print in
ASCII, we've always printed to either an HP LaserJet or an Apple LaserWriter,
and they both understand enough PCL to get by.

Thus the original contention remains more right than wrong: none of this is
the fault of the little JetDirect EX Plus cards; it's a spooler problem.

Where is Larry Byler when you need him?

Wirt Atmar