A computer system is provided to use a function of a plurality of signal interface protocols separately corresponding to a plurality of signal lines by extracting pin output of one slot included in a PCI(Peripheral Component Interconnect) slot corresponding to the signal lines and adding the extracted pin output to another slot. A first slot(10) supports a plurality of signal interface protocols corresponding to a plurality of signal lines. A second slot(20) supports one of the signal interface protocols. The first and second slots have an integration type. The first slot supports a PCI signal interface protocol and a USB(Universal Serial Bus) signal interface protocol selectively, and the second slot supports the USB signal interface protocol. Pin output needed for the signal interface protocol supported by the second slot is extracted from the first slot.
