B8ZS
Abbreviation for bipolar with eight-zero substitution. A T-carrier line code in which bipolar violations are deliberately inserted if user data contains a string of 8 or more consecutive zeros.
Note 1: B8ZS is used to ensure a sufficient number of transitions to maintain system synchronization when the user data stream contains an insufficient number of “ones” to do so.
Note 2: B8ZS is used in the European hierarchy at the T1 rate.