I have a customer with an OSR 5.0.7 MP4 system, using a print-server
that doesn't support direct printing using netcat and therefore has to
be used via LPD.

Mostly this works but occasionally the lpd process hangs. I note that
syslog contains many messages saying the printer "doesn't support the
extended protocol"

This is strange since I didn't configure the printer with SCO's
proprietary "extended protocol" - there is certainly no ":ex:" in
/etc/printcap.

I have suggested replacing the print server (A Dynamode 3-parallel-port
device) with a Jetdirect or D-Link (which are OK in my experience).

I've searched in SCO TA and Googled c.u.s.m in vain. Does anyone have
any ideas about the cause of the message?