B6ZS

Abbreviation for bipolar with six-zero substitution. A T-carrier line code in which bipolar violations are deliberately inserted if user data contain a string of 6 or more consecutive zeros. A code in which eight consecutive zeros are replaced with the sequence 000+-0-+ if the preceding pulse was + and with the sequence 000-+0+- of the preceding pulse was -, where + represents a positive pulse, – represents a negative pulse, and 0 represents no pulse. Note 1: B6ZS 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: B6ZS is used in the North American hierarchy at the T2 rate.