Communication Slot Description and Compatibility

This article provides a description and compatibility information for the Comm Slot I and Comm Slot II used in various Power Macintosh computers.
Overview
There are two unique comm slots used in older Macintosh and Power Macintosh computers. They are generally not compatible with each other.

The logic board in the Power Macintosh 5400 and 6400; Performa 6400 series; Performa 6360/160; Power Macintosh 4400 series; Power Macintosh 6500; and Twentieth Anniversary Macintosh has a PCI-bus based communications slot connector referred to as Comm Slot II. The connector is a 112-pin half-height microchannel style. Cards that use the communications slot are memory mapped into the I/O space of these computers through the parallel bus.

Compatibility

The communications slots in the above mentioned computers are, in general, not compatible with communication cards that are used with the Macintosh LC family of computers, the Macintosh 630 series, or Power Macintosh 5200, 5300, 6200, and 6300 series computers. For more information about the communications slot used with Power Macintosh 5200, 5300, 6200, and 6300 series computers, please see the following Tech Info Library article:

Article 15081: Communication Slot: Specifications

Such cards will not physically fit into the communications slot of the Power Macintosh 5400 and 6400; Macintosh Performa 6400 series; Macintosh Performa 6360/160 computers; Macintosh Performa 4400; Power Macintosh 6500; and Twentieth Anniversary Macintosh systems because the communications slot is keyed at the opposite end (notches). If you line up the notches to install a comm slot I card* into these computers, the connector will face inwards, which prevents you from being able to use the card. In addition, the two communications slots are not fully signal compatible.

The exception is that cards which do not use the bus, such as serial modem cards, can be designed to work in either type of communications slot. The power, ground, serial, and audio signals of the communications slots in the Power Macintosh 5400 and 6400; Macintosh Performa 6400 series; Macintosh Performa 6360/160 computers; Power Macintosh 4400 series; Power Macintosh 6500; and Twentieth Anniversary Macintosh systems are located on the connector in such a way that a dual-keyed (cutout) modem card will fit and operate in the Macintosh LC family of computers, the Macintosh 630 series, or Power Macintosh 5200, 5300, 6200, 6300 series computers, and Power Macintosh 5400 and 6400; Macintosh Performa 6400 series; Macintosh Performa 6360/160 computers; Power Macintosh 6500; and Twentieth Anniversary Macintosh systems communications slot.

Serial modems designed for universal operation must not attempt to access the parallel bus of either the 68030-bus or the PCI-bus communications slots to be compatible in both configurations.

*Note: To distinguish between those cards that are compatible with the Power Macintosh 5400 and 6400; Macintosh Performa 6400 series; Macintosh Performa 6360/160 computers; Power Macintosh 400 series; Power Macintosh 6500; and Twentieth Anniversary Macintosh systems from those compatible with earlier models, the communication slots themselves are named distinctly. The communications slot in previous models is referred to as "comm slot I" whereas the slots in the Power Macintosh 5400 and Macintosh Performa 6400 are called "comm slot II".

Installation

A communications card can be installed by either the user or an Apple-authorized Service Provider. The communications card is mounted vertically in the connector and its I/O connector is accessed through the communications port access hold on the right hand side of the back panel.

Available Cards

Apple announced several Ethernet CS II (Communication Slot II), including:
The Power Macintosh 5400/120 and the Power Macintosh 6400/200 include the 10BaseT Ethernet CS II Card, but it and the other cards will also be available as standalone cards as well. The Macintosh Performa 6400 series and the Macintosh Performa 6360/160 computers do not include an Ethernet Card, but they do have an internal 28.8 kBps Global Village or Apple GeoPort modem installed in the communications slot.

Note: The following computers are in the corresponding Macintosh families:
Published Date: Feb 18, 2012