Apple III

The Apple III was Apple Computer, Inc.'s first business-oriented personal computer, introduced in May 1980 as the intended successor to the successful Apple II Plus. Designed for professional and corporate users, it featured a new operating system, more memory, and advanced display capabilities, but suffered from reliability issues that impacted its commercial success.

Apple III

Apple III personal computer
Specifications
Manufacturer	Apple Computer, Inc.
Type	Business Computer
Released	May 1980
Discontinued	April 24, 1984
Intro price	US$4,340 (base, 1980)
CPU	Synertek 6502A @ 2 MHz
Memory	128 KB RAM (expandable to 512 KB)
Storage	Built-in 140 KB 5.25" floppy drive, optional external floppy and ProFile hard disk
Display	24 lines × 80 columns text; 560×192 graphics (monochrome)
Sound	1-bit beeper
Dimensions	12 cm × 40 cm × 45 cm
Weight	10.9 kg (24 lb)
OS / Firmware	Apple SOS (Sophisticated Operating System), Apple III BASIC
Successor	Apple III Plus
Codename	Sara
Model no.	A3S1, A3S2, A3S3

Architecture and Processor

The Apple III utilised a Synertek 6502A microprocessor running at 2 MHz—double the clock speed of the Apple II series. The system architecture was designed to be compatible at a hardware level with Apple II software (in a special emulation mode), but primarily targeted new business applications written for its advanced feature set.

Key architectural features included:

• Synertek 6502A CPU @ 2 MHz
• Custom Apple-designed logic for memory management and video
• Hardware support for 80-column text and high-resolution monochrome graphics
• Separate character generator ROM for business-oriented text display

Memory and Storage

The Apple III shipped standard with 128 KB of RAM, expandable up to 512 KB via internal memory boards—significantly more than its predecessor. ROM included the Apple III BASIC interpreter and system firmware.

Storage options:

• Built-in 140 KB 5.25" floppy disk drive (single-sided, single-density)
• Support for up to three external floppy drives
• Optional ProFile hard disk drive (5 MB) via interface card

Display and Graphics

The Apple III introduced advanced display capabilities for its time:

• Text modes: 24 lines × 80 columns (business standard), 24 × 40 mode for Apple II compatibility
• Graphics modes: 560×192 pixels (monochrome), 280×192 (6 colours, Apple II compatible)
• Programmable character generator for custom fonts and internationalisation

The 80-column text and high-resolution graphics made the Apple III suitable for word processing, spreadsheets, and business graphics.

Sound Capabilities

Sound on the Apple III was basic, provided by a 1-bit beeper controlled directly by the CPU. This was similar to the Apple II and limited to simple tones and alerts.

Input/Output and Expansion

The Apple III offered a range of I/O and expansion options:

• Serial ports: Two RS-232C-compatible DB-25 connectors for printers and modems
• Parallel port: Optional via interface card
• Video output: Composite video for monochrome or colour monitors
• Keyboard: Full-stroke, 74-key keyboard with numeric keypad
• Expansion slots: Four internal slots compatible with most Apple II peripheral cards
• External drive port: For additional floppy or ProFile hard disk

These features allowed the Apple III to connect to a variety of business peripherals and expand its capabilities as needed.

Gallery

• 
  Apple III keyboard with numeric keypad
• 
  Apple III internal view (logic board and drive)

Related Pages

• Apple III Plus