Command Reference Guide

3Com Router 5000 Family and Router 6000 Family ft1 data-coding ● 183
Command Reference
ft1 data-coding
Purpose Use the ft1 data-coding normal command to disable user data inversion on
the T1-F interface.
Use the
ft1 data-coding inverted command to enable user data inversion on
the CT1/PRI interface.
Use the undo ft1 data-coding command to restore the default.
Syntax ft1 data-coding { normal | inverted }
undo ft1 data-coding
Parameters normal
Disables user data inversion.
inverted
Enables user data inversion.
Default By default, data inversion is disabled.
Example Enable user data inversion on the T1-F interface.
[Router-Serial0/0/0] ft1 data-coding inverted
View This command can be used in the following views:
■ T1-F Interface view
Description To prevent 7e in valid data from being taken for stuffing characters, HDLC inserts a
zero after every five ones in the data stream. Then, HDLC inverts every one bit into a
zero and every zero bit into a one. This ensures at least at least one out of every eight
bits is a one. When AMI encoding is adopted on a T1-F interface, the use of data
inversion can eliminate presence of multiple consecutive zeros.
At the two ends of a T1-F line, the same data inversion setting must be adopted.