functions:obstacle test, independent ringing, calling user, matching line, monitoring and high- ... , S-100 Telephone Line Checker adds other functions such as obstacle test, independent ringing, calling user, matching line, monitoring and high ... ): 146×54×379. Weight: <=220g 1. Dial, call, ring 2. Obstacle test:. Call the user and talk back 4. Matching line5 ...