| 摘要 |
A data collecting system is divided into first, second, and third information portions and includes at least one portable terminal for collecting data at a remote site. The terminal comprises a device for collecting data and a first memory for storing the first information portion. The terminal operates to sense the need for information for its use to generate an information call identifying the information and to respond to the information call for searching its memory for the information. If the information is available it is supplied for use by the portable terminal. The system further comprises a first mobile server which comprises a second memory for storing the second information portion, and responds to the information call for searching the second memory for the information. The system further includes a second server at a main information center. The second server comprises a third memory for storing the third information portion, and searches the third memory for the information. The data collection terminal is responsive to the absence of the information within the first memory for transmitting from the calling terminal the information call via a first communication link to the first mobile server. The mobile server responds to the receipt of the information call to search the second memory for the information and, if present, accessing the information from the second memory and transmitting it via the first communication link for use by the calling terminal. |
