| 摘要 |
<p>PURPOSE:To contrive to reduce the overhead of a host computer and to realize reduction of the line traffic by detecting and controlling the information signal for state of terminal power supply in a fixed cycle via an HUB provided to a LAN of a star-shaped connection and to coping with the state change of the power supply. CONSTITUTION:An HUB receives an informing signal (sig) which shows the ON state of a power supply to which a terminal equipment outputs the (sig) in a fixed cycle at an OFF mode of a data transmission request signal in an OFF mode of a signal BUSY showing a data transfer state, and detects the ON state of the power supply to hold and control this detection output while the retrigger modes are repeated in a fixed cycle. Then the HUB outputs the signal (sig) to all terminal equipments when the power supply of the terminal equipment has a change. Each terminal outputs an interruption request to a host CPU and the CPU decides that either one of those terminal equipments has a change of its power supply state to apply polling to all terminal equipments. As a result, the signal (sig) is not received directly to reduce the overhead of a host computer to contrive to reduce the line traffic.</p> |
