Apple ColorLaserWriter 12/600PS - Manual (Page 281)

Controller
m AMD Am29030 25-MHz microprocessor
m 8 MB of ROM (including 39 Type 1 fonts)
m 12 MB of RAM (expandable to 40 MB)
m 128 KB parameter SRAM
m SCSI interface for internal/external hard disk(s)
m LocalTalk interface
m High-speed parallel interface (IEEE P1284 ECP, bidirectional)
m Ethernet interface with three protocols:
EtherTalk
Novell NetWare IPX (PSERVER or RPRINTER)
TCP/IP (BSD lpd )
m External Ethernet transceivers available for:
Thin Coaxial
Twisted Pair (10Base-T)
Thick Coaxial (IEEE 802.3 AUI)
m Two-position communication configuration switch
m All ports/protocols simultaneously active
m Color-rendering acceleration
m Data compression/decompression system
m Forgery tracking system
m Adobe PostScript Level 2 (version 2014)
Theory of operation
Here is an abbreviated summary of how the printer operates:
m Controller sends a compressed page to the video ASIC (application-specific
integrated circuit), which decompresses the page at once and sends it to the
laser circuitry in the engine.
m The laser, on a scan-line-by-scan-line basis, pulses color by color and
paints each successive layer of the image on the photoconductor drum. The
color order is magenta-cyan-yellow-black. Laser light hits the
photoconductor on all the dots where toner should appear.
258 Appendix A