The Fault Mapper Pro? Model CA7027 is a hand-held graphical TDR (Time Domain Reflectometer) designed for identifying and locating faults on power and communication cables, given access to one end only. The Fault Mapper Pro? measures cable length and indicates the length and distance to cable faults to a range of 9 ft (3 m) to 19,000 ft (6000m) on virtually any type of cable. It injects a series of pulses into the cable under test. The velocity at which the pulses travel is determined by the type of cable, which is known as the velocity of propagation (Vp) of the cable. The Velocity of Propagation (Vp) is adjustable between 1% and 99% enabling accurate calibration to the cable under test. The Vp value is expressed as a percentage of the speed of light (e.g. 67% or ft/mtrs/micro-second), this value will vary according to the type of cable under test. The Fault Mapper Pro? can accept user selectable values between 1 and 99% (or the equivalent value in feet or meters per micro-second). Based on the selected Vp and the time taken for the pulses to travel through the cable, a reflection profile of the cable under test is displayed. An adjustable cursor assists in locating faults and termination. The Fault Mapper Pro? incorporates an oscillating tone tracer, which is detectable with a standard tone tracer, for use in the tracing and identification of cable pairs.