They do not work with LocalTalk or MIDI devices. They also are compatible limited range of a printers. And their software may conflict with other system resources. The number one customer request to date has been for an iMac version of the Stealth Serial Port. The Stealth for the iMac is not a general purpose solution, but one that targets specific needs of customers willing to make the tradeoff of the modem to gain other functionality.
Installation takes a bit longer to install than a RAM upgrade.
The modem resides on the underside of the logic board. To access the modem slot, a few screws fastening the logic board and the side metal fence must be removed. The Stealth Serial Port for the G4, G3 and iMac are shipping and available to order today. The Stealth Serial Port installs in minutes with just a screwdriver. The internal modem card and the Stealth Serial Port's interface card uses the same slot on the mother board.