Bit stuffing

In data transmission and telecommunication, bit stuffing (also known—uncommonly—as positive justification) is the insertion of non information bits into data. Stuffed bits should not be confused with overhead bits.

Bit stuffing is used for various purposes, such as for bringing bit streams that do not necessarily have the same or rationally related bit rates up to a common rate, or to fill buffers or frames. The location of the stuffing bits is communicated to the receiving end of the data link, where these extra bits are removed to return the bit streams to their original bit rates or form. Bit stuffing may be used to synchronize several channels before multiplexing or to rate-match two single channels to each other.