LOOP BACK

1. A method of performing transmission tests of access lines from the serving switching center , which method usually does not require the assistance of personnel at the served terminal . ( 188 ) 2. A method of testing between stations (not necessarily adjacent) wherein two lines are used, with the testing being done at one station and the two lines interconnected at the distant station. ( 188 ) 3. A patch , applied manually or automatically, remotely or locally, that facilitates a loop -back test.