Flag sequence
Encyclopedia
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.
Note 2: Flag sequences are used in bit-oriented protocols, such as Advanced Data Communication Control Procedures
(ADCCP), Synchronous Data Link Control
(SDLC), and High-Level Data Link Control
(HDLC).
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...
or processing, a 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...
of bits used to delimit, i.e. mark the beginning and end of a frame.
Note 1: An 8-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 is usually used as the flag
Flag (computing)
In computer programming, flag can refer to one or more bits that are used to store a binary value or code that has an assigned meaning, but can refer to uses of other data types...
sequence; for example, the 8-bit flag sequence 01111110.
Note 2: Flag sequences are used in bit-oriented protocols, such as Advanced Data Communication Control Procedures
Advanced Data Communication Control Procedures
In telecommunication, Advanced Data Communication Control Procedures is a bit-oriented data link layer protocol used to provide point-to-point and point-to-multipoint transmission of data frames that contain error control information. It places data on a network and ensures proper delivery to a...
(ADCCP), Synchronous Data Link Control
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...
(SDLC), and High-Level Data Link Control
High-Level Data Link Control
High-Level Data Link Control is a bit-oriented synchronous data link layer protocol developed by the International Organization for Standardization...
(HDLC).