Line code
Pattern used within a communications system to represent digital data / From Wikipedia, the free encyclopedia
In telecommunication, a line code is a pattern of voltage, current, or photons used to represent digital data transmitted down a communication channel or written to a storage medium. This repertoire of signals is usually called a constrained code in data storage systems.[1] Some signals are more prone to error than others as the physics of the communication channel or storage medium constrains the repertoire of signals that can be used reliably.[2]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/55/NRZcode.png/220px-NRZcode.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b6/Ami_encoding.svg/640px-Ami_encoding.svg.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/9/98/Manchester_code.svg/220px-Manchester_code.svg.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/0/04/Differential_manchester_encoding_Workaround.svg/320px-Differential_manchester_encoding_Workaround.svg.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Biphase_Mark_Code.svg/320px-Biphase_Mark_Code.svg.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b4/MLT3encoding.svg/640px-MLT3encoding.svg.png)
Common line encodings are unipolar, polar, bipolar, and Manchester code.