| 摘要 |
PURPOSE:To secure the function test with the single unit of the communication control unit by installing within the communication control unit the clock oscillator of the same frequency as the clock of the monitor device plus the delay memory featuring the equal time to the loop transmission delay time each. CONSTITUTION:When the single unit test mode is designated through the control panel, the clock sent from clock oscillation circuit 8 in the communication control unit is supplied to each part in place of the clock which is sent from the monitor device to repeater 2 via transmission line 1. And the data from control part 4 is sent to transmission part 5 via frame buffer memory 7. The data of the serial bits sent from part 5 is supplied to reception part 3 and then returned to part 4 again. As the delay time of memory 7 is equal to the loop delay time on the transmission line, the artifitial loop is formed within the communication control unit. Thus the data read out of memory 7 can be seen as if it were just on the transmission line. As a result, each block within the communication control unit features nearly the same operation as that of the normal operation, thus enabling the test with the single unit. |
