| 摘要 |
PURPOSE: To provide a means which can test pair lines in a customer machine, even in a digital loop transmission system which uses optical fibers reaching a distant terminal. CONSTITUTION: The digital loop transmission system consists of a center station terminal 10, a remote terminal 12 connected optically and electrically to the center station terminal, and a distant terminal 16 optically connected to the remote terminal. In this system, the distant terminal 16 is provided with a drop test module 20, which tests a fault of a line 18 in the customer machine and a means which optically transmits the test result to the remote terminal 12 through an optical data link 17. The remote terminal 12 is provided with a means which converts the test result to a characteristic resistance, and this characteristic resistance is set so as to be accessed electrically by the center station terminal 10. |
