Because Xircom® RealPort Integrated PC Cards are Type III PC Cards, they utilize both slots. What if I need my second slot for an additional PC Card?

Xircom®  RealPort Integrated PC Cards are designed to incorporate the features most commonly used by the mobile user. These include a 10Mbps or 10/100Mbps Ethernet LAN, 56K modem, and telephone pass-through connectors. They also include optional ISDN and GSM capabilities. If other functions are necessary, RealPort Integrated PC Cards support hot swapping.

This applies to:

Xircom® CardBus Ethernet 10/100 Adapter (CBE-10/100BTX) Xircom® CardBus Ethernet II 10/100 Adapter (CBE2-100) Xircom® RealPort™ CardBus Ethernet 10/100 Adapter (RBE-100) Xircom® RealPort2™ CardBus Ethernet 10/100 Adapter (R2BE-100)