Patent ID: 8416700

Claim:
A method comprising: directing, by a digital subscriber line access multiplexer, a residential gateway to configure a first end of a transmission loop as an open loop, wherein the first end of the transmission loop terminates at the residential gateway and wherein a second end of the transmission loop terminates at the digital subscriber line access multiplexer; performing, by the digital subscriber line access multiplexer, a first single-ended loop test at the second end of the transmission loop responsive to directing the residential gateway to configure the first end of the transmission loop as an open loop; directing, by the digital subscriber line access multiplexer, the residential gateway to configure the first end of the transmission loop as a terminated-loop responsive to performing the first single-ended loop test; performing, by the digital subscriber line access multiplexer, a second single-ended loop test at the second end of the transmission loop responsive to directing the residential gateway to configure the transmission loop as a terminated-loop; subtracting, by the digital subscriber line access multiplexer, a first trace associated with the first single-ended loop test from a second trace associated with the second single-ended loop test to obtain a third trace; and determining, by the digital subscriber line access multiplexer, a length of the transmission loop from the third trace.