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. They are 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.
The syntax of ptal-connect and ptal-print is as follows:
ptal-connect [devname] action [options...]
ptal-print [devname] [options...]
- devname is the optional PTAL
- action specifies the remote service and is one of:
- -print -- the print service (the default for ptal-print)
- -scan -- the scan service
- -socket socketID -- a particular remote socket ID
- -service serviceName -- a particular remote service name
- options... is zero or more of:
- -eoftimeout seconds -- Idle timeout before exiting
after an end-of-file condition is encountered on standard input
- -fwdlen maxForwardDatalen -- Forward data packet size
requested to be negotiated with the device
- -revlen maxReverseDatalen -- Reverse data packet size
requested to be negotiated with the device
- -retrycount seconds -- Maximum number of times to
retry a failed connection (default is 10)
- -noretry -- Disables retries of failed connections
(same as "-retrycount 0")
- -infretry -- Retries failed connections forever
(same as "-retrycount -1")
- -retrydelay seconds -- Delay between each retry
(default is 1)
- -quiet -- Disables "connecting" message
- -uel, -nouel -- Enables/disables print job boundary
escape sequences (default is disabled)
- -dump -- Dumps data structures (for debugging)
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 is used by ptal-cups (the PTAL
CUPS backend) to pass printer-ready data
to the device.
"-service ECHO" is useful for verifying basic device connectivity,
because text you send in the forward direction is echoed in the reverse
direction. (However, this service may not work properly on the OfficeJet
LX and 300 series.)
-scan only connects to the scan service on the device and doesn't
in an of itself start a scan operation; use
libsane-hpoj for that.
It is not recommended to call "ptal-connect -scan" directly,
because in certain cases it may make the scan service unusable for subsequent
actual scans (due to improper negotiated packet sizes) until the device is
power-cycled or ptal-mlcd is restarted.
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.
Specifying -infretry causes failed connection attempts to be retried
indefinitely, even in situations where the connection would never be
successful. Other (non-negative) retry options may cause fewer retries than
expected, depending on the nature of the connection failure.
If you're connecting through an HP JetDirect print server (i.e. with a
PTAL device name prefix of hpjd:), then the following limitations
- -scan, -socket, and -service require a
JetDirect model with multi-function peripheral support:
- Parallel-port JetDirects: 70X, 170X, 300X, or 500X only
- USB JetDirects: 175X and probably later models
- -scan requires firmware x.07.xx or later.
- -socket and -service require firmware x.08.xx or
- For parallel-port JetDirects, -socket and -service
are only supported for devices running in 1284.4 (not MLC) mode.
For USB JetDirects, they are supported in both modes.
- A limited number of clients may have -socket and
-service connections to the same device at any given time,
even if they are to different services.
- -fwdlen and -revlen requests are ignored.