Loopback?(loop-back) refers to the routing of electronic signals, digital data streams, or flows of items back to their originating devices or facilities without intentional processing or modification. This is primarily a means of testing the transmission or transportation infrastructure.
Example applications:
- A communication channel with only one?endpoint. Any message transmitted by such a?channel?is immediately and only received by that same channel.
- Performing?transmission?tests of?access?lines from the serving?switching center, which usually does not require the assistance of personnel at the served terminal.
- Testing between stations (not necessarily adjacent) where in two lines are used, with the test being done at one station and the two lines interconnected at the distant station. Commonly called?loop around?when the interconnecting circuit is accessed by dialing.
- A?patch cable, applied manually or automatically, remotely or locally, that facilitates a loop-back test.
