This article provides technical specifications for the PowerBook 540c computer.

• 66/33-MHz 68LC040 microprocessor (no FPU). (the two speeds refer to the internal processor and bus interface, respectively)
• 32-bit Address and Data bus
• Daughterboard (memory expansion) has a 32-bit bus running at 33MHz

• 4 MB RAM on logic board.
• Expandable to 36 MB with 70ns low power self-refreshing RAM (Apple 8 MB RAM Expansion Kit, or Third Party higher density RAM card)

• One built-in 1.4 MB Apple SuperDrive disk drive that uses high-density floppy disks; it reads, writes, and formats Macintosh, MS-DOS, OS/2, and ProDOS disks.
• One internal 320 MB hard disk.

• Serial/LocalTalk
• Built-in High Speed Ethernet with Apple AUI connector

• Nickel-metal-hydride PowerBook Intelligent Batteries each provide up to 3.5 hours of use before recharge.
• EverWatch battery-saver technology
• Batteries recharge in two hours when computer is in sleep or shutdown; four hours when running.
• PowerBook Control Strip allows user to monitor time remaining, charge time, and battery usage
• Backup rechargeable lithium battery maintains RAM in sleep modem while main battery is removed for up to three minutes.

• Built-in keyboard with standard size keyboard with 76 (US) or 77 (ISO) keys including 12 function keys
• Two-level tilt adjustment
• Power-on key located on Keyboard
• Solid-state trackpad provides precise cursor control in response to the user's fingertip over its surface

• One Apple Desktop Bus (ADB) port for keyboard, mouse, and other devices.
• One RS-422 serial port for LocalTalk networking, printers, modems, and other devices.
• One high-speed Ethernet port
• One HDI-30 SCSI port for hard disks, scanners, CD-ROM drives, and other devices (up to 6 devices can be chained).
• One slot for optional modem.
• One video-out port, supporting 8 bit density and 256 colors.
• One stereo sound output port for external audio amplifier or headphones.
• One mono sound-in port.
• Security slot for use with third-party equipment to lock the computer.
• 90-pin processor direct slot (PDS) for connecting PDS devices or optional
• PowerBook PCMCIA Expansion Module allows use of two Type II or one Type III PCMCIA-type card).
• One RAM slot

• CD-quality, 16-bit stereo sound capable of driving headphones or other stereo equipment.
• Two built-in stereo speakers
• Digital-to-analog and analog-to-digital conversion sampled at 11.035, 22.050, or 44.100 kHz.

• Operating temperature: 50 to 104 F (10 to 40 C)
• Storage Temperature: -40F to +149F (-40 to +65 C)
• Relative humidity: 20% to 80% noncondensing
• Altitude: max. 10,000 ft. (3,048 m)
• Maximum Storage Altitude: 15,000 ft. (4,722 m)

• Height: 2.3 in. (5.7 cm)
• Width: 11.5 in. (29.2 cm)
• Depth: 9.7 in. (24.5 cm)
• Weight: 7.3 lb. (3.3 kg)