Abstract: A portable data storage device includes a control unit coupled via a predetermined interface with a computer having an operating system with user authority limits, and a memory divided into a segment I for storing related applications, a public segment II for temporarily storing instructions and data, and a hidden segment III for saving client data. In a method of accessing data via the portable data storage device, when the computer is to write data into or read data from the segment III, the data to be written or read is first temporarily stored in the segment II, and specific read or write instructions for a read/write level application interface are written into the segment II by the applications in the segment I and executed, so as to complete data exchange and access between the portable data storage device and the computer.

Abstract: An audio signal transmitting apparatus utilizes an encoder/decoder and an audio signal controller to convert an audio signal received by a mobile phone into a file executable by a computer system, and also can convert an audio message of the computer system into an audio signal transmissible by the mobile phone. The invention includes an encoder/decoder, an audio signal controller coupled to the encoder/decoder, and a plurality of audio transmission interfaces respectively coupled with the encoder/decoder and the audio signal controller.

Abstract: A portable data storage device includes a control unit coupled via a predetermined interface with a computer having an operating system with user authority limits, and a memory divided into a segment I for storing related applications, a public segment II for temporarily storing instructions and data, and a hidden segment III for saving client data. In a method of accessing data via the portable data storage device, when the computer is to write data into or read data from the segment III, the data to be written or read is first temporarily stored in the segment II, and specific read or write instructions for a read/write level application interface are written into the segment II by the applications in the segment I and executed, so as to complete data exchange and access between the portable data storage device and the computer.

Abstract: A portable data storage device allowing dynamic setting of disk type thereof includes a flash memory that includes at least two segments preset as a CD-ROM segment and a fixed type hard drive segment. When the portable data storage device is plugged in a processing unit of an electronic apparatus, one of the two segments having a non-applicable disk type is hidden depending on an operating system under which the processing unit operates, so that the processing unit may detect only another one of the two segments that has an applicable disk type. A method for dynamically setting an applicable disk type of the portable data storage device is also provided.

Abstract: A portable data storage device is characterized in having an internal file and a start program separately pre-recorded in predetermined segments on a flash memory of the device, an encryption mechanism for protecting the device against arbitrary access, and auto-execution ability like a compact disk. With these arrangements, it is ensured the start program is automatically executed without any user operation to play the internal file each time the portable data storage device is used. And, the internal file is effectively protected from deletion, unauthorized copy, or theft.