Where do I find information about JetDirect printing?

CUPS consists of a Unix print spooler and scheduler, a filter system that converts the print data to a format that the printer will understand, and a backend system that sends this data to the print device. CUPS uses the Internet Printing Protocol (IPP) as the basis for managing print jobs and queues. It also provides the traditional System V and Berkeley command line interfaces, along with limited support for the server message block protocol (SMB). The device drivers CUPS supplies can be configured by using text files in Adobe's PostScript Printer Description (PPD) format. There are a number of user interfaces for different platforms that can configure CUPS, and it has a built-in web-based interface. CUPS is provided under the GNU General Public License and GNU Lesser General Public License, Version 2.