Cisco ASR 9000 Series Command Reference Manual page 1011

T3, E3, T1, E1 Controller Commands on the Cisco ASR 9000 Series Router
down-when-looped (T1/E1)
Related Commands
Command Description
loopback (T1/E1), on page 1023 Loops individual T1 or E1 channels on the channelized T3
controller.
Cisco ASR 9000 Series Aggregation Services Router Interface and Hardware Component Command Reference,
Release 5.3.x
991