Zero-Bit Insertion

What Does Zero-Bit Insertion Mean?

Zero-bit insertion is a bit-stuffing technique in which a zero bit is inserted after a series of one bits to highlight a sequence change or break. Zero-bit insertion is used with other bit-oriented protocols to prevent the accidental appearance of six consecutive one bits between the two framing flags indicating a transmission frame’s beginning and end.


Techopedia Explains Zero-Bit Insertion

Zero-bit transmission is widely used in IBM’s High-Level Data Link Control (HDLC) – a data link format structure. The HDLC format requires that a frame’s beginning and end be flagged. Zero-bit insertion is generally used to distinguish between the flag pattern and data of the same format. The flag byte normally contains the bit sequence “01111110.”

To keep the flag byte bit sequence from occurring within the transmission frame, the HDLC transmitter inserts a zero after five consecutive bits. The only drawback of the zero-bit insertion technique is its irregular code or information rate.


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Margaret Rouse

Margaret Rouse is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical, business audience. Over the past twenty years her explanations have appeared on TechTarget websites and she's been cited as an authority in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine and Discovery Magazine.Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages. If you have a suggestion for a new definition or how to improve a technical explanation, please email Margaret or contact her…