The Loop a Line has been a Telstra standard for 20 years. It is probably the simplest time saving device available for contractors and technicians. Once fitted to the far end of a line you can switch between Open, Short, Connect, 600 ohm, and Tone modes allowing all installation and fault location to be performed from the one end without having to go back and forward from one end of the line to the other. For example, a single technician working alone, can connect the remote unit to the exchange MDF, street cabinet, or distribution point in tone mode. That same technician can then go to the far end of the line and: Identify the pair using tone mode Switch the mode to open or short from the far end to enable connection of other test equipment for testing such as: Foreign battery Insulation resistance Loop resistance Resistance and balance measurements Fault location using testers such as TDRs, bridges, and Multifunction units Switch the mode to Connect to reconnect the customer service and perform dial or call back checks
