The Apple Internet Router 3.0.1 software is the only Apple Internet Router software compatible with the Power Macintosh systems. There is one compatibility situation to be aware of: Power Macintosh systems allow only one NuBus card to be a bus master.
Because of this, it is not possible to have more than one Apple Serial NB Card installed in a Power Macintosh system. The Ethernet NB Card and Apple Token Ring NB/c Cards are not bus master cards so there are no problems with these cards.
The Apple Token Ring 4/16 NB Card is a little more complicated. When this card is used with driver software from NSI 1.4.4 and earlier, it is a bus master card and may not be used in conjunction with another bus master card on a Power Macintosh system.
NSI 1.4.5 contains new drivers for the Apple Token Ring 4/16 NB Card. These drivers are what we would call "dumb" drivers. With the Apple Token Ring 4/16 NB Card driver, the 68000 processor on card is not used at all. This is a good thing for most situations. The driver is faster than the old driver and has an added benefit of not putting the card in bus master mode. This means more than one card can be installed in a Power Macintosh system. The only caveat here is the dumb driver does not work with the SNA*ps Gateway product. A "smart" driver is included on the NSI 1.4.5 disk just for the SNA*ps Gateway product. This driver puts the card in bus master mode.
Another issue to note here is that it is not possible to have the "dumb" and "smart" drivers for the Apple Token Ring 4/16 NB Card installed and used at the same time. If both drivers are installed, the "smart" driver will be used.
The Apple Token Ring NB/c Card is never in bus master mode and has only one driver. This driver does not support the SNA*ps Gateway product at this time.
Support Information Services