Digital Lines Test Set, ADSL
The TX120A is a low cost, multi-function test instrument, primarily for determining the suitability of twisted copper pairs for use by Pair Gain Systems, ISDN and HDSL but with application in the testing of such pairs for normal telephone services. Loading coils, build-out capacitors and surge protection devices are necessary components of many POTS lines. Bridged taps, split pairs, poor joints and leaky insulation are conditions that are undesirable but often tolerated on POTS lines. However, all of these conditions seriously affect the operation of high frequency systems and must, therefore, be found and eliminated or corrected before such systems can be installed. The TX120A consists of three main components. The SENDER is connected to one end of the line at the exchange, pillar or pit. The RECEIVER is connected to the other end of the line and displays all test results and controls the function of the SENDER. The PROBE is used, if necessary, to identify the pair under test.