The Apple II

Apple II

The Apple II is an 8-bit home computer, one of the first highly successful mass-produced microcomputer products, designed primarily by Steve Wozniak, manufactured by Apple Computer and introduced in 1977...

 line of computers supported a number of Apple II peripheral cards, expansion cards which plugged into slots on the motherboard, and added to and extended the functionality of the base system.

All Apple II models except the Apple IIc

Apple IIc

The Apple IIc, the fourth model in the Apple II series of personal computers, was Apple Computer’s first endeavor to produce a portable computer. The end result was a notebook-sized version of the Apple II that could be transported from place to place...

 had at least seven 50-pin expansion slots, labeled Slots 1 though 7. These slots could hold printed circuit board

Printed circuit board

A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...

 cards with double-sided edge connector

Edge connector

An edge connector is the portion of a printed circuit board consisting of traces leading to the edge of the board that are intended to plug into a matching socket. The edge connector is a money-saving device because it only requires a single discrete female connector , and they also tend to be...

s, 25 "fingers" on each side, with 100 mil

Thou (unit of length)

A thou also known as a mil or point, is the verbalized abbreviation for "thousandth of an inch." It is a unit of length equal to 0.001 inch....

 (0.1 inch) spacing between centers.

In addition to the seven standard expansion slots, the following computers contained additional, largely special-purpose expansion slots:

• Apple II and Apple II Plus
  Apple II Plus
  The Apple II Plus was the second model of the Apple II series of personal computers produced by Apple Computer, Inc. It was sold new from June 1979 to December 1982.-Features:...
  
  : Slot 0 (50-pin, for the firmware card or the 16 kB
  Kilobyte
  The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
  
   Apple II Language Card)
• Apple IIe
  Apple IIe
  The Apple IIe is the third model in the Apple II series of personal computers produced by Apple Computer. The e in the name stands for enhanced, referring to the fact that several popular features were now built-in that were only available as upgrades and add-ons in earlier models...
  
  : Auxiliary Slot (60-pin; primarily for 80-column display and memory expansion)
• Apple IIGS
  Apple IIGS
  The Apple , the fifth and most powerful model in the Apple II series of personal computers produced by Apple Computer. The "GS" in the name stands for Graphics and Sound, referring to its enhanced graphics and sound capabilities, both of which greatly surpassed previous models of the line...
  
  : Memory Expansion Slot (40-pin)

Perhaps the most common cards found on early Apple II systems were the Disk II

Disk II

The Disk II Floppy Disk Subsystem was a 5¼-inch floppy disk drive designed by Steve Wozniak and manufactured by Apple Computer. It was first introduced in 1978 at a retail price of US$495 for pre-order; it was later sold for $595 including the controller card and cable...

 Controller Card, which allowed users of earlier Apple II's to use the Apple Disk II, a 5¼ inch, 140 kB floppy disk drive; and the Apple 16K Language Card, which increased the base memory of late-model Apple II and standard Apple II Plus units from 48 kB to 64 kB.

Both Apple

Apple Computer

Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...

, and dozens of third-party vendors created hundreds of cards for the Apple II series of computers. These expansion slots afforded great opportunities for expansion. In the 2000s, long after the last Apple IIe

Apple IIe

The Apple IIe is the third model in the Apple II series of personal computers produced by Apple Computer. The e in the name stands for enhanced, referring to the fact that several popular features were now built-in that were only available as upgrades and add-ons in earlier models...

 came off Apple's assembly line in 1993, a handful of manufacturers continue to market peripheral

Peripheral

A peripheral is a device attached to a host computer, but not part of it, and is more or less dependent on the host. It expands the host's capabilities, but does not form part of the core computer architecture....

s and expansion cards for Apple II computers, not counting students, hobbyists, and other Apple II users who continue to push the original machine to its limits.

50-pin standard slots

• Serial cards
  Apple II serial cards
  Apple II serial cards primarily used the serial RS-232 protocol. They most often were used for communicating with printers, Modems, and less often for computer to computer data transfer. They could be programmed to interface with any number of external devices which were RS-232 compatible...
  
   (RS-232 serial interface)
• Parallel cards (Centronics/IEEE 1284 parallel interface)
• Multifunction I/O cards
• Internal modems
• 80 column (or more) text cards (e.g., Videx
  Videx
  Videx is a manufacturer of access control products and data collection terminals. Better known in the 1980s as manufacturer of Videx VideoTerm and Videx UltraTerm add-on expansion card for Apple II computers...
  
  )
• RGB cards
• Floppy disk controllers
• Hard disk controllers
• Network adapters
• Co-processor cards
  Apple II processor cards
  Apple II processor cards were special cards that could be used to allow the Apple II to use different processors on the same hardware...
  
  
• Memory expansion cards
• Accelerators
  Apple II accelerators
  Apple II accelerators are computer hardware devices which enable an Apple II computer to operate faster than their intended clock rate.Starting in 1977, most Apple II computers operated at a speed of 1 megahertz . That precedent was finally broken 10 years later in 1987 with the introduction of...
  
  
• Realtime clock cards
  Apple II system clocks
  Apple II system clocks, also known as real-time clocks, were commodities in the early days of computing. A clock/calendar did not become standard in the Apple II line of computers until 1987 with the introduction of the Apple IIGS...
  
  
• Music and sound cards
  Apple II sound cards
  The Apple II had limited sound capabilities until the Apple //gs shipped in 1986. Many third-party manufacturers made sound cards to enablericher sound output.- Mockingboard :...
  
  
• Miscellaneous cards

Other slot types

• Slot 0 card (Firmware Card, Language Card)
• Apple IIc internal expansion cards
• Apple IIGS memory expansion cards (40-pin IIGS slot type)
• Apple IIGS accelerators
• Apple IIe auxiliary cards (60-pin auxiliary slot; 80-column cards, RGB, memory expansion)

Manufacturers

• ReactiveMicro.com — Hard drive controllers, GS-RAM card, Mockingboard clone, replacement power supplies, No-Slot Clock, MicroDrive, TransWarp GS 32KB Cache Board, other TransWarp GS upgrades
• R & D Automation — CFFA Compact Flash, IDE interface card
• A2 Retrosystems — Uther Ethernet card
• SVD — Semi Virtual Diskette, solid-state 5¼" disk emulator
• ///SHH Systeme — hard and floppy drive controllers, LANceGS Ethernet Card, TransWarp 32-kB cache board
• 8 Bit Baby — prototyping board
• RC Systems — DoubleTalk (Echo and Slotbuster compatible) speech synthesizer card