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international alphabet 5 (IA5)

International alphabet number 5 according to ITU T.50 (V.4) or ISO 646. A 7-bit computer code for the representation of a total of 128 alphanumeric characters, digits, special characters and control characters, derived from the ASCII code and based on a joint ISO/ITU recommendation.

Division of the code table

The code table is divided into 15 rows and 8 columns. To determine an alphanumeric character or a control character, the rows and columns can be displayed in decimal, hexadecimal or binary notation. A distinction is made between text characters (digits, special characters) and control characters. The desired messages are formed from the text characters, the control characters are used for information exchange in older character-oriented transmission protocols.

7-bit code, international version

7-bit code, international version

These control characters are divided into the six functional groups: Transmission Control Characters, Format Control Characters, Device Control Characters, Information Separators, Code Expansion Control Characters, and Other Control Characters. Start of Heading( SOH), Start of Text( STX), End of Text ( ETX), End of Transmisison ( EOT), Enquiry( ENQ), Acknowledgment ( ACK), Data Link Escape ( DLE), Negative Acknowledgement ( NAK), Synchronization ( SYN) and End of TransmissionBlock ( ETB) belong to the first group. These characters are used exclusively to control the operational flow between two or more data stations.

Format control characters Backspace( BS), Horizontal Tabulation ( HT), Line Feed( LF), Vertical Tabulation ( VT), Form Feed( FF) and Carriage Return( CR) determine the arrangement of the transmitted data on the devices for input and output.

Device Control characters are used to switch additional and auxiliary devices on and off. It is the Device Control, with DC1 to DC4.

The information separators Unit Separator, End of Intermediate Transmission block( US/1TB), Record Separator( RS), Group Separator( GS) and File Separator( FS) provide the logical structure of the data.

The characters Shift Out ( SO), Shift In( SI) and Escape Character( ESC) serve as control characters for the code extension. These characters can be used to extend the supply of characters and form other control characters. Other control characters include Zero( NUL), Bell ( BEL), Cancel( CAN), End of Medium( EM), Substitute Character ( SUB), Space( SP), and Delete( DEL).

Other control characters of the IA-5 alphabet

Other control characters of the IA-5 alphabet

Other names for the IA-5 alphabet are ISO 7-bit code, CCITT code No. 5, ECMA 7-bit code, DIN 66 003 code, USASCII or ASCII character set and international code for data transmission in digital data networks.

In addition to the international version, there are also national versions of the 7-bit code: a German and an American version, in which special national characters are assigned to certain bit combinations.

Informations:
Englisch: international alphabet 5 - IA5
Updated at: 09.11.2013
#Words: 416
Links: alphabet, international telecommunication union (ITU), international organization for standardization (ISO), computer, code
Translations: DE
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