3Com 3031 Command Reference Manual page 195

Fundamental CE3 Interface Configuration Commands 195
If a CE3 interface encapsulated with PPP has been set to perform loopback, it is
normal for the state of the link layer protocol to be reported as DOWN.
Example
Enable the interface E3 1/0/0 to perform local loopback.
[3com-E3 1/0/0] loopback local
national-bit
Syntax
national-bit { 0 | 1 }
undo national-bit
View
CE3 interface view
Parameter
0: Sets the national bit of the CE3 interface to 0.
1: Sets the national bit of the CE3 interface to 1.
Description
Using the national-bit command, you can configure national bit for a CE3
interface. Using the undo national-bit command, you can restore the default
setting.
The national bit of CE3 interface defaults to 1.
It is necessary to set the national bit of an E3 interface to 0 only in some special
circumstances.
For the related command, see controller e3.
Example
Set the national bit of the interface E3 1/0/0 to 0.
[3com-E3 1/0/0] national-bit 0
using Syntax
using { e3 | ce3 }
undo using
View
CE3 interface view