Newer JetDirect adapters supports FTP printing, simply upload the file you want to print.
Alternatively, send the print jobs directly to the printer via the LPR/BSD protocol on port TCP/515. This ancient protocol is supported even by the oldest JetDirect cards and can be used in several different ways.
1. Use LPRng (by far the simplest approach)
"cat printme.txt | lpr -h @192.168.1.2"
2. If you are using Perl, download and install Net::Printer from
www.CPAN.org3. Write your own TCP client that speaks LPR/BSD (The protocol is very very simple)
More information can be found in this excellent tutorial on printing and network print spoolers:
http://www.lprng.org/LISA98.ppt