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You can configure this command only when the T1 line is working in framed
format (which can be set by using the undo t1 unframed command).
Related command: t1 unframed.
Example # Set the framing format to SF for the first T1 line on interface T3 2/0.
<Sysname> system-view
[Sysname] interface t3 2/0
[Sysname-T3 2/0] t1 1 set frame-format sf
t1 set loopback
Syntax t1 line-number set loopback { local | remote | payload }
undo t1 line-number set loopback
View CT3 interface view
Parameter line-number: T1 line number in the range 1 to 28.
local: Sets the T1 line in internal loopback mode.
remote: Sets the T1 line in external loopback mode.
remote: Sets the T1 line in payload loopback mode.
Description Use the
t1 set loopback command to set the loopback mode of a T1 line on the
T3 interface.
Use the
undo t1 set loopback command to disable the T1 line to loop back.
By default, loopback is disabled on T1 lines.
Loopback is intended for test use. Disable it otherwise.
If a T1 line encapsulated with PPP is placed in loopback mode, it is normal that the
state of the link layer protocol is reported down.
Example # Enable internal loopback on the first T1 line on interface T3 2/0.
<Sysname> system-view
[Sysname] interface t3 2/0
[Sysname-T3 2/0] t1 1 set loopback local
t1 set fdl
Syntax t1 line-number set fdl { ansi | att | both | none}
undo t1 line-number set fdl
