1) Communication circuit
Found on
https://www.crosswordclues.com/clue/loopback
Loopback, or loop-back, refers to the routing of electronic signals, digital data streams, or flows of items back to their source without intentional processing or modification. This is primarily a means of testing the transmission or transportation infrastructure. Many example applications exist. It may be a communication channel with only one co...
Found on
http://en.wikipedia.org/wiki/Loopback
a device incorporated in a terminal equipment or at a given point in the network for redirecting the information flow in the opposite direction from the receive path to the corresponding transmit path at this point, for testing purposes from a control point
Found on
http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=716-01-23
Diagnostic test where the transmitted signal is returned to the sending device after passing through a datacomms link or network.
Found on
http://www.encyclo.co.uk/visitor-contributions.php
Directing signals back toward the transmitting terminal at some point along the communications path. Used as a method of troubleshooting.
Found on
https://www.encyclo.co.uk/local/20850
No exact match found.
