Power Macintosh G3: Ethernet/Comm Slot Support

This article explains the Communications Slot (Comm Slot) on Power Macintosh G3 computers, and which kinds of cards may be used with them.

This article has been archived and is no longer updated by Apple.
The Communications Slot architecture was introduced in 1994 as an extra slot that would provide customers with the ability of using inexpensive communications cards, such as Ethernet and modem cards. These slots were mainly made available on entry-level systems. This architecture predated the widespread adoption of the Peripheral Component Interconnect (PCI) architecture by the computer industry, which turned out to be another way for users to inexpensively add capabilities to their computers.

The original Comm Slot architecture was known as Comm Slot I, and was the one used on computers such as the Power Macintosh 6200, 6300, 5200, and 5300.

The Comm Slot II architecture is used with the Power Macintosh 5400, 6360, 6400, and 6500 series computers, as well as the Twentieth Anniversary Macintosh.

The two architectures share similar features, but they are not identical. To prevent the wrong card from being used, notches are placed on the connector in various locations. This prevents the wrong card from being used.

Cards which are designed for both types of slots are called "universal" cards.

G3 computers support a new "personality card" architecture, which is used in a slot, known as a PERCH slot, on the logic board. Two personality cards are currently available for this slot. Each card provides sound support for the computer, as well as a modem slot on the card. The A/V card also works with video in and out.

The PERCH slot on the logic board is not a Comm Slot. This slot cannot be used for any type of Comm Slot II-capable card.

The slot on the personality card uses the same connector as a Comm Slot II connector, and Comm Slot II cards will fit. However, the slot on the personality card is a modem slot, only providing serial support for Comm Slot II-capable modems. This slot does not work with Ethernet cards, and should not be regarded as a Comm Slot II slot.

When a modem is plugged into the slot on the personality card, the external modem port on the back of the computer is disabled.

If you require an alternate Ethernet solution beyond that which is provided with the RJ-45 10T port that comes with all G3 computers, you may wish to explore a third-party PCI Ethernet card.
Published Date: Feb 20, 2012