Voltcraft ct 20tdr cable tester voltcraft ct 20tdr p the voltcraft ct 20tdr is a multifunction lan cable tester that enables the checking of 2 to 8 pin cables and their shielding there are 5 test modes to choose from lan mode the phone mode coax mode tracking mode and linear mode in each mode specific cable and number of cores can be chosen the test procedure is automatic and the results are displayed graphically and in plain easy to understand text p p what s in the box br rem