3Com 3032 Configuration Manual page 155

Table 178 Set loopback mode of the CT3 interface
Operation
Set loopback mode of CT3 interface
Disable loopback on the CT3 interface
Difference between two types of external loopback of the CT3 interface: Frame
header overhead should be processed for external payload loopback (payload)
while frame is not processed for external remote loopback (remote).
By default, loopback is disabled.
Single-channel loopback can be set on the T1 channels on a CT3 interface, and
the settings of individual channels are independent.
Table 179 Set loopback mode of T1 channel
Operation
Set loopback mode of T1 channel
Disable loopback on the T1 channel
By default, loopback is disabled.
5 Set Frame Format
Two frame formats are used on CT3 interface: M23 and C-bit.
Perform the following configuration in CT3 interface view.
Table 180 Set frame format of the CT3 interface
Operation
Set CT3 frame format
Restore the default setting
By default, the CT3 interface uses the C-bit frame format.
When CT3 interface work in CT3 mode, single-channel frame format can be set
on the T1 channels, and the settings of individual channels are independent.
Perform the following configurations in CT3 interface view.
Table 181 Set the frame format of T1 channel
Operation
Set the frame format of T1 channel
Restore the frame format of T1 channel to the
default value
By default, the frame format of T1 channel is ESF.
6 Configure Operate Mode of CT3 Interface
When setting the operating mode of a CT3 interface, you should set the operating
modes of both the CT3 interface and the T1 channels on the interface.
Perform the following configuration in CT3 interface view.
Table 182 Set the operating mode of CT3 interface
Operation
Configure Operate Mode of CT3 Interface
Restore Operate Mode of CT3 Interface to default
CT3 Interface
Command
loopback { local | payload |
remote }
undo loopback
Command
t1 line-number set loopback { local
| remote }
undo t1 line-number set loopback
Command
frame-format { c-bit | m23 }
undo frame-format
Command
frame-format { sf | esf }
undo frame-format
Command
using { t3 | ct3 }
undo using
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