Abstract: A method and apparatus for testing a subscriber line of a communication exchange. A telephone coupled to the subscriber line is used to dial first and second specified telephone numbers to couple the subscriber line to a bit error rate measurement device, housed in a talking circuit switch, and to designate channels of the subscriber line to be tested. The bit error rate measurement device transmits bit error rate measurement signals through the designated channels and uses these bit error rate measurement signals to generate bit error rate signals indicating the bit error rates of the channels. The bit error rates are represented as audible sounds transmitted to the telephone. Accordingly, it is possible to start the test from customer station equipment, to evaluate the quality of digital transmission through the channels, and to specify the fault points of the channels by repeating bit error rate measurements in different channel paths.