These are
Postscript level 2 printers that do not support LPR/LPD. All these printers are LocalTalk printers. Except for those marked (Ethernet) they also need a converter from AppleTalk-over-Ethernet to AppleTalk/LocalTalk to print from Macs newer than the Beige G3 and with Mac OS X through 10.5.
Personal LaserWriter NTR
Personal LaserWriter 320
LaserWriter Select 360
LaserWriter 4/600 PS
LaserWriter IIf
LaserWriter IIg (Ethernet)
LaserWriter Pro 600
LaserWriter Pro 630 (Ethernet)
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Appletalk Printer Access Protocol has been dropped from Mac OS X 10.6 Snow Leopard.
There was a substantial discussion about this issue recently, which ran over a hundred posts:
http://discussions.apple.com/thread.jspa?threadID=2073321&tstart=0
To summarize, your options are:
• Get a USB-to-parallel or USB-to-serial converter to plug into some other port on the printer.
• Get a Mac running pre-Snow_Leopard, connect it to your network, and have it share the printer with the other Macs. Peggy, queen of the AppleWorks forum, suggests using a Mac Mini. An old laptop may also be a solution.
• Get a third-party printerserver from a major vendor such as Hewlett-Packard.