Apple upped the ante by moving from the 68030 to the 68LC040 processor on the Duo 280 and 280c in May 1994. (The 68LC040 is a low power version of the 68040 with the internal FPU disabled.) Other than the CPU, this is essentially a Duo 270c .

Like the 270c, the 280c supports 16-bit video if you select the 640 x 400 pixel mode under Options in the Monitors control panel.

Specs (via Low End Mac)

• Cpu: 33 MHz 68LC040
• Ram: 4 MB, expandable to 40 MB using a single Duo RAM card
• Rom: 1 MB
• Display: 8.4″ 640 x 480 @ 8-bits, 640 x 400 @ 16-bits, 95 ppi active matrix
• Gestalt Id: 103
• Weight: 4.8 pounds
• Adb Port: only with dock
• Scsi Port: only with dock
• Serial Ports: 1 DIN-8 RS-422 port on back of computer
• Power Supply: M2693
• See: O nline resources and links for the PowerBook Duo 280c