In telecommunication

Telecommunication

Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...

, bit-sequence independence is a characteristic of some digital

Digital

A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...

 data transmission

Data transmission

Data transmission, digital transmission, or digital communications is the physical transfer of data over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibres, wireless communication channels, and storage media...

 systems that impose no restrictions on, or modification of, the transmitted bit

Bit

A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...

 sequence

Sequence

In mathematics, a sequence is an ordered list of objects . Like a set, it contains members , and the number of terms is called the length of the sequence. Unlike a set, order matters, and exactly the same elements can appear multiple times at different positions in the sequence...

.

Bit-sequence-independent protocols are in contrast to protocols that reserve certain bit sequences for special meanings, such as the flag sequence

Flag sequence

Flag sequence: In data transmission or processing, a sequence of bits used to delimit, i.e. mark the beginning and end of a frame.Note 1: An 8-bit sequence is usually used as the flag sequence; for example, the 8-bit flag sequence 01111110....

, 01111110, for HDLC, SDLC

Synchronous Data Link Control

Synchronous Data Link Control is a computer communications protocol. It is the layer 2 protocol for IBM's Systems Network Architecture . SDLC supports multipoint links as well as error correction. It also runs under the assumption that an SNA header is present after the SDLC header...

, and ADCCP protocols.

Bit-sequence-independence allows only line codes that have the same number of transitions per bit, otherwise, the line code is dependent on the bit sequence and, therefore, bit-sequence dependent.