| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the number of terminals which are set when the terminal increases to one and to eliminate the trouble to change the number of the terminals by instructing a sending-out means to send a response signal out when the address that a polling signal indicates exceeds the total number of the terminals. SOLUTION: A receiving terminal when having a transmit message at the time of the reception of a polling signal addressed to itself sends the message to a data communication line 10, but when there is not transmit message, the terminal sends EOT indicating the release of a data link to the data communication line 10. When the set number (n) of terminals 12-#i is larger than (m), a polling signal are sent out of the terminals 12-#i until addresses (m+1) to (n) regardless of no corresponding terminal. Then a receiving terminal 18 receives and outputs the polling signals to a monitor means 22. The monitor means 22 monitors the addresses of the polling signals and instructs a sending- out means 20 to send EOT out when the address is larger than (m).</p> |
