PURPOSE: To easily find out the defect of a transmission line or a slave station and to attain preventive maintenance of the transmission line by providing a transmission management counter to a master station equipment so as to manage a reply data from the slave station.
CONSTITUTION: When a reply data from slave stations 11, 12 is normally received by a retrial polling, since the number of times of disabled reception is stored in a transmission management counter 101 of the master station 10, the operator freely reads the stored value of the counter. That is, the transmission management counter 101 stores the count for the slave stations 11, 12. Thus, when a count of a transmission management counter of all slave stations is read, and the count of the slave stations 11, 12 is more than that of other slave stations, it is judged that the quality of the transmission line L1 after the branch from the transmission line L0 is deteriorated or the connection of the branch point between the transmission lines L0 and L1 is defective.
MIURA NAOTO
KONO HIROKI
SUZUKI HIROSHI
TOSHIBA CORP
| JPS61227443A | 1986-10-09 | |||
| JPS6083432A | 1985-05-11 | |||
| JPS6047534A | 1985-03-14 |