A portable computer system includes a portable computer and an integrated device both having wireless data transmission interface. The integrated device is connected to various peripheral devices with different interfaces and controlled by corresponding external port signals. When the portable computer wants to access the peripheral devices, a signal processor integrates and encodes all the external port signals to generate a single encoded signal to be fed to the integrated devices via the wireless transmission interface. After the integrated device receives the encoded signal, a signal processor decodes it to reproduce individual external port signals to be transferred to each corresponding peripheral device to control the operation thereof. During the encoding process, the signal processor may set the priorities according to the properties of each signal and add the identification information of the portable computer. Then, the signal processor integrates the priorities, identification information and all external port signals and produces the encoded signal. Since the encoded signal includes the user information, different users may simultaneously access the peripherals to achieve the object of peripheral-sharing.