Abstract: Determining distance to echo points on a wire-line medium from a testing point. A sequence of test bits may be transmitted from one end (testing point) of a wire-line medium. An echo is deemed to be received if a monitored bit stream equals/matches the transmitted sequence. The distance to the echo point is computed by multiplying half the time to receive the echo with a velocity of propagation of the bits. In an embodiment, the transmitted sequence is chosen to exhibit good auto-correlation property, which enables the reception of the echo to be determined reliably.