PJL in script or C

[Tim Howell]

I need to check the status of a network printer, preferable within the (ANSI C) application, before the application sends a job to the printer. It sounds like PJL is the key, but I can't find difinitve docs or examples. I even have the printed book from HP, but there are too many unknowns left to perform the task. It says there is a way to receive messages from the printer, but it doesn't explain how. I am using HP-UX 11i, korn shell, and have laserjet4v and 5000N printers.
Thanks in advance!

[Rodney Hills]

If I'm not mistaken, most status checks of network devices (including printers) is done via "snmp".

-- Rod Hills

[Johan_52]

You open a TCP connection with the printer and send a PJL command to retrieve the status of the device with commands like @PJL INFO VARIABLES or @PJL INQUIRE . This will return amongst lots of other information messages like toner low, paper out etc. Personally I prefer unsolicitied status messages (@PJL USTATUSON) The printer sends device/job/page message when a particular event occurs (the device goes offline, a job is printed or a page is complete). This requires that when you're sending data to the printer you periodically read from the port to see if there are any messages pending.

[Tim Howell]

Thanks Rod, I will investigate that as well.

Johan, I have tried that but got no response. Perhaps I did not do it right. I treated the printer as the server and had the tcp client connect on port 9100. (I stumbled on that port in the hpnpf man page)I achieved a connection and sent commands, but the printer did not return anything...(?)

Thanks again.

[Johan_52 · Accepted solution]

Hi Tim

The attached [ modified ] excerpt from my pjl driver retrieves the configuration information from a PJL printer. I know the recv loop could be implemented smarter, but as is it shows best what needs to be done.
Compile with the -D_SOCKET_SOURCE and -D_HPUX_SOURCE options and execute specifying the printer name and port on the command line. If this example does not work I think you should check printer and / or network settings, but I'm afraid I can't help you there much further.

HTH

Johan