| 摘要 |
PURPOSE:To secure the measurement for the transmission quality without sending the measurer to the remote place but by inserting the 3rd data communication unit to the circuit between the 1st and 2nd data communication units and then carrying out the measurement of the transmission quality among the circuit communication sections as well as the calculation of the measurement result through the 3rd data communication unit. CONSTITUTION:The 3rd data communication unit 18 is connected to circuit 13 between data communication units 12 and 14 which are connected to the 1st and 2nd terminals 11 and 15, and switch part 19 is provided to unit 18. Furthermore, loop test information generator circuit 21, transmission quality reception circuit 22 for the high-input impedance and transmission quality reception circuit 23 for the characteristic impedance are connected to unit 18 via part 19. And also computer 24 is installed when necessary. Thus the loop test information sent from unit 18 is detected at units 12 and 14, and the detected information is received in turn at circuits 22 and 23 of unit 18. Then the transmission quality is measured for the information of units 12 and 14 plus terminals 11 and 15 each, the facilitating the maintenance of the circuit. |
