Macintosh PowerBook 550c (1995)

The PowerBook 500 series (codenamed Blackbird, which it shared with the older Macintosh IIfx) is a range of Apple Macintosh PowerBook portable computers first introduced by Apple Computer with the 540c model on May 16, 1994. The 500 series was the first laptop computer to use a trackpad instead of a trackball as a built-in pointing device and the first to have Ethernet networking built-in. It was the first PowerBook series to use a Motorola 68LC040 CPU (simultaneous with Duo 280) and be upgradeable to the PowerPC architecture via a swap out CPU daughter card (with the PowerPC and 68040 upgrades for sale), use 9.5" Dual Scan passive color/B&W displays, 16bit stereo sound with stereo speakers, have an expansion bay, PC Card capability, two battery bays (and a ten minute sleep/clock battery, which allowed for main batteries to be swapped out while in sleep mode), full size keyboard with F1-F12 function keys, be able to sleep while connected to an external monitor and have a battery contact cover included on the actual batteries. It included a single serial port which could be to connect to a serial printer or a network via Apple's LocalTalk. In another first, it also included an AAUI port for connecting to non-LocalTalk (usually Ethernet) networks. It was introduced on May 16, 1994 with the expensive active matrix LCD PowerBook 540c and 540, with the passive matrix 520c and 520 soon after. 

via Wikipedia: http://en.wikipedia.org/wiki/PowerBook_500_series