What you descirbe may occur with PowerBook G3 and 3400 computers as well as PowerBook 2400 computers.
The PowerBook G3, PowerBook 3400, and PowerBook 2400 all use Card & Sockets Service 3.0. If the PC Card has supporting software, which needs to be installed, it must be Card & Sockets Service 3.0 compliant. Almost all third-party vendors have updated their software to work with this new standard. It is possible that the combo card (Ethernet and Modem combination PC card) will perform as a modem but Ethernet functionality will be disabled. This also happens if the driver software does not support Card & Socket Services 3.0.
The Tech Info Library article titled "
Locating Vendor Information" can help you search for a particular vendor's address and phone number.