Print Files
The HP Jetdirect FTP server transfers print files to the printer but does not interpret them. For proper printing, print files must be in a language recognized by the printer (such as PostScript, PCL, or unformatted text). For formatted print jobs, you must first print to a file from your application using the driver for the selected printer, then transfer the print file to the printer through an FTP session. For formatted print files, use binary (image) type transfers.
Using FTP Printing
FTP Connections
Similar to standard FTP file transfers, FTP printing uses two TCP connections: a control connection and a data connection.
Once an FTP session is opened, it remains active until either the client closes the connection or the data and control connections are idle for 900 seconds (15 minutes). (This setting cannot be configured.)
Control Connection
Using standard FTP, a control connection is opened by the client to the FTP server on the HP Jetdirect print server. FTP control connections are used to exchange commands between the client and the FTP server. The HP Jetdirect print server supports up to three control connections (or FTP sessions) simultaneously. If the number of allowed connections is exceeded, a message indicating that service is not available will be displayed.
FTP control connections use TCP port 21.
Data Connection
A second connection, a data connection, is created each time a file is transferred between the client and the FTP server. The client controls the creation of a data connection by issuing the commands that require a data connection (such as FTP ls, dir or put commands).
54 FTP Printing
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