Okidata 320T printer at a remote location hangs in the middle of print jobs, at random times and intervals, and at random points in the page header (apparently). The print head just stops moving, and I think the printer just drops out of SEL mode, but w/o any flashing lights, etc. It then must be power cycled and the print job resent, though occasionally the job will finish printing but on the wrong line. Printer is connected to the network via HP JetDirect print server. I have swapped out printers, print servers, and printer ports on server with no change.
Jobs are printed from remote client (on Win2k) to main app server (on SCO Unix) at home office, which then sends job back to remote printer. Error can occur under any user account or during print function (as far as we can tell).
Sites are linked by 384k VPN tunnel, with priority to VPN traffic. Latency is normally about 40ms. LAN at remote site is totally clean, no packets dropped, but is still using a hub rather than a switch. There is infrequent packet loss and increased latency between sites, but I have not been able associate printer problem with any such network event. That seems the most likely scenario, but the connection is normally very stable and other sites with much worse connections do not have this problem (or have never called me about it.) Nobody remembers if this started before or after switching from Frame to VPN, of course.
My next step will be to hook up a packet sniffer on the remote LAN to see if I can catch the packets when the printer hangs, and to try to get a temporal match on the network-VPN status and printer errors. I will probably put a switch out there, too. Much to the dismay of the users there, I am pretty much at a loss for other avenues or explanations at this point, and the Unix support people were not much help either. The users really did not like the deal-with-it solution.