Mac OS X: Using LocalTalk Hardware and Serial Port Devices
Mac OS X does not work with LocalTalk hardware. A third-party Ethernet-to-LocalTalk adapter may allow you to use your LocalTalk device with Mac OS X. You can find such adapters at the Macintosh Products Guide. Check the third-party manufacturer's specifications for Mac OS X compatibility.
Alternatively, you can restart the computer with Mac OS 9.1 to use a LocalTalk device.
For more information, see technical document106170: "Mac OS X 10.0: Classic Does Not Allow Direct Hardware Networking Access."
Note: LocalTalk (hardware) should not be confused with AppleTalk (a networking protocol). You can use AppleTalk devices with Mac OS X, as long as they are not connected to an external serial port with LocalTalk hardware.
Serial Port-Based Modems
Mac OS X is compatible with serial port-based modems and PPP connections. Serial port-based modems work with PPP applications such as Mail and Microsoft Internet Explorer, both natively and in the Classic environment. Use the Mac OS X Internet Connect application to make the PPP connection if needed, but afterwards you may use a Classic PPP application successfully.
Classic (non-PPP) modem software, such as a Classic fax application or a terminal emulation application, will not work. If you need to use this software, start up with Mac OS 9.1.
Other Serial Port-Based Hardware
Other hardware devices that use a serial port do not work in the Mac OS X Classic environment, but they may work in the native Mac OS X environments. Verify compatibility of the hardware in question with the product's manufacturer.
If you use a device that adds a serial port to a computer that did not originally come with one (such as a GeeThree Stealth Serial Port, or Griffin Technology gPort or CubePort), you should verify compatibility information of the device with the manufacturer.