Classic Computer Magazine Archive COMPUTE! ISSUE 71 / APRIL 1986 / PAGE 10

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The Editors and Readers of COMPUTE!

Apple IIe/lIc Compatibility
I'm interested in buying an Apple IIc computer. Can it use IIe hardware and software?
Carlos Aguayo

The Apple IIc computer is basically an Apple IIe that has been redesigned to take up as little space as possible. To keep the IIc small, Apple left out the II's expansion slots (where additional hardware can be attached), but added a built-in 5¼-inch disk drive. They also put the most common IIe expansion hardware (80-column video display, an extra 64K of memory, and two serial input/output ports) on the main board of the IIc. In addition, the IIc has some features that weren't available when the IIe appeared: an advanced 65C02 microprocessor and a character set called Mousetext which contains extra characters especially for Macintosh-style icon- and menu-based programs. The newest version of the IIe (called Enhanced IIe) does have these extra features; dealers can upgrade an older IIe at a small cost.
    The IIc can run almost all IIe programs, as long as no special hardware is required. For instance, some music programs can communicate with instruments through a MIDI (Musical Instrument Digital Interface) adapter. This adapter must connect to an expansion slot, which is possible only on a IIe. Other programs sometimes expect a parallel I/O interface to attach a printer. Since the IIc has only serial I/O, it can't run that type of modification. Although the IIc has no expansion slots, its peripherals (serial ports, disk drives, etc.) act like they are built into certain slots. Apple tried to select the most commonly used slot for each peripheral (printer in slot 1, disk drive in slot 6). However, not everyone puts everything in the same place, and some programs may demand an unconventional configuration. Ile owners can rearrange the cards in their slots to run such programs, but IIc owners don't have this option.
    The serial ports on the IIc generate standard RS-232 signals which can be used to communicate with most modems from any manufacturer. Many of the most popular printers are also available with RS-232 interfaces. But the IIc does not have standard connectors for these ports. To save space on the back panel of the computer, DIN-type connectors are used instead; as a result, you'll need special cables (available from Apple dealers) to attach serial peripherals.
    When it comes to expandability, the IIe is much more flexible than the IIc. Almost any kind of peripheral can be attached through one of its slots, including parallel I/O ports, MIDI interfaces, hard disk drives, coprocessors, huge RAM expansion cards, and a host of other devices. However, some third-party companies have begun modifying the IIc to put in extras like additional memory and Z80 processors (to run the CP/M operating system, a popular IIe add-on). It's still more difficult than expanding a IIe, but it can be done.