• Also known as
  • American Standard Code for Information Interchange

ASCII is the abbre­vi­a­tion for Amer­i­can Stan­dard Code for Infor­ma­tion Inter­change, a char­ac­ter encod­ing stan­dard for elec­tronic com­mu­ni­ca­tion. Orig­i­nally cre­ated for tele­type machines, ASCII codes rep­re­sent text in telecom­mu­ni­ca­tions equip­ment, com­put­ers, and other devices.

Based on the Eng­lish alpha­bet, ASCII encodes 128 spec­i­fied char­ac­ters into seven-bit inte­gers. Ninety-five of the encoded char­ac­ters are print­able: these include the dig­its 0 to 9, low­er­case let­ters a to z, upper­case let­ters A to Z, and punc­tu­a­tion sym­bols. In addi­tion, the orig­i­nal ASCII spec­i­fi­ca­tion included 33 non-print­ing con­trol codes which orig­i­nated with Tele­type machines; most of these are now obso­lete, although a few are still com­monly used, such as the car­riage return, line feed and tab codes.

As com­puter tech­nol­ogy spread through­out the world, dif­fer­ent stan­dards bod­ies and cor­po­ra­tions devel­oped many vari­a­tions of ASCII. These newer char­ac­ter-encod­ing schemes often are based on ASCII, but typ­i­cally sup­port addi­tional char­ac­ters, e.g. to facil­i­tate the expres­sion of non-Eng­lish lan­guages that use Roman-based alpha­bets, scripts and sym­bols.

The most com­mon char­ac­ter set sup­plant­ing ASCII nowa­days is Uni­code. While Uni­code still incor­po­rates the orig­i­nal ASCII codes, its ver­sion Uni­code 11.0 from June 2018 con­tains a reper­toire of 137,439 char­ac­ters cov­er­ing 146 mod­ern and his­toric scripts, as well as mul­ti­ple sym­bol sets and emoji.