The HP LaserJet 5Si printer is a high-volume, 24-ppm workhorse laser printer designed to handle the print needs of large networks and departments. It's an improvement in every way over its award-winning predecessor, the HP LaserJet 4Si printer -- faster, more robust and more intelligent. The printer is also versatile. It offers paper-handling and network options that let you build exactly the printer you need. Product differences: The 5siNX is a 5si with built-in ethernet networking, similarly a 5siMX is designed with built-in networking for a Macintosh environment. c3166a.