hpoj reference: ptal-connect and ptal-print

The ptal-connect command-line utility provides access to the various stream services on the device. ptal-print is a symlink alias for ptal-connect that defaults to connecting to the print service. It is similar to a telnet client, in that once connected to the service on the device, data on standard input is sent to the device over the open channel as "forward" data, and any "reverse" data received from the device over the open channel is sent to standard output.

Syntax

The syntax of ptal-connect and ptal-print is as follows:
	ptal-connect [devname] action [options...]
	ptal-print [devname] [options...]
Where:

Notes

Service name lookup is part of the 1284.4 protocol, and is simulated by ptal-mlcd and by the JetDirect firmware for MLC mode. Therefore, you should usually be able to specify the service name for well-known services. For other services, you may need to specify both -service for 1284.4 mode and -socket for MLC mode.

-print, "-service ECHO", and possibly -scan are the most common device services one would typically want to connect to. ECHO and -scan are mainly useful for testing and debugging connectivity. (Note that -scan doesn't in and of itself start a scan operation; use libsane-hpoj for that.)

ptal-mlcd supports several "virtual" services which do not involve the device in any way.

Most if not all devices have a limit of one connection to each service at any given time. Subsequent connections will fail.

The "datalen" parameters to -fwdlen and -revlen do not include the 6-byte header inherent in the MLC and 1284.4 protocols. The requested sizes are not guaranteed to be honored, because the device is permitted to reduce either or both sizes. For MLC mode, the negotiated packet sizes for a given service are fixed after the first negotiation, and subsequent requests are ignored. For 1284.4 mode, different sizes may be honored each time. Some combinations of sizes may have erroneous results on some models.

If you're connecting through an HP JetDirect print server (i.e. with a PTAL device name prefix of hpjd:), then the following limitations apply: