thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Networking Fundamentals · Intermediate

Time-Domain Reflectometer (TDR)

An instrument that sends a pulse down a copper cable and times reflections to locate breaks, shorts, kinks and impedance changes.

Definition

A TDR reports the distance to a fault, which is useful in long runs inside walls. Many cable certifiers and some switches include TDR functions.

Example

A TDR shows an open 47 m from the patch panel.

Exam tip

TDR = copper; OTDR = fiber.

Related terms