3Com 3032 Configuration Manual page 149

If T1-F interface is used as DCE, the slave clock should be selected. If it is used as
DTE, the master clock should be selected.
If the T1-F interfaces of two routers are directly connected, they must respectively
work in slave and master clock modes. If the T1-F interface of the router is
connected to an exchange, however, the exchange is working as DCE and
provides clock, so the interface of the router should work in master clock mode.
Perform the following configuration in T1-F interface view.
Table 160 Set line clock for a T1-F interface
Operation
Set line clock for a T1-F interface
Restore the line clock of the T1-F interface to the default
setting
By default, the clock of T1-F interface is slave clock.
6 Set Interface Frame Format
T1-F interfaces support Supper Frame (SF) and Extended Supper Frame (ESF). In SF,
multiple frames can share the same frame synchronization and signaling
information, so that more significant bits can be used for transmitting user data. In
practice, the system test is often required. The application of ESF technology can
ensure normal service when the system test is being carried out.
Perform the following configuration in T1-F interface view.
Table 161 Set frame format of T1-F interface
Operation
Set frame format for a T1-F interface
Restore the default frame format of T1-F interface
By default, the frame format of T1-F interface is ESF.
7 Enable or Disable Local Loopback/Remote Loopback
An interface should be place in local loopback or remote loopback for some
special functionality tests.
Perform the following configuration in T1-F interface view.
Table 162 Enable/Disable local/remote loopback on a T1-F interface
Operation
Enable local/remote loopback on an interface
Disable local/remote loopback on an interface
By default, no T1-F interface is placed in local or remote loopback.
On an interface, using this command but with different arguments can
respectively enable local loopback and remote loopback, but these two functions
cannot be enabled at the same time.
T1-F Interface
Command
ft1 clock { master |
slave }
undo ft1 clock
Command
ft1 frame-format { sf |
esf }
undo ft1 frame-format
Command
ft1 loopback { local |
remote }
undo ft1 loopback [
local | remote ]
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