ISO-IR-153


ISO-IR-153 is an 8-bit character set that covers the Russian and Bulgarian alphabets. Unlike the KOI encodings, this encoding lists the Cyrillic letters in their correct traditional order. This has become the basis for ISO/IEC 8859-5 and the Cyrillic Unicode block.

Standards and Naming

ISO-IR-153 is a subset of ISO/IEC 8859-5. The ISO-IR-153 documentation cites ST SEV 358-88 as the source standard. While it also cites the earlier GOST 19768-74, it does not follow the KOI-8 layout so this appears to be in error. The ISO-IR-153 encoding was intended to replace GOST 19768-74, and is sometimes referred to as GOST-19768-87. This confusion has led to a common misconception that ISO-8859-5 was defined in or based on GOST 19768-74.
Notwithstanding the extents of their accuracy, the IANA lists, and as labels which may be used for the ISO-IR-153 encoding on the Internet, with reference to RFC 1345, which assigns it those labels.
GOST R 34.303-92 includes the ISO-IR-153 code page and dubs it KOI-8 V1.

Character set

The following table shows the ISO-IR-153 encoding. Each character is shown with its equivalent Unicode code point.
The encoding closely resembles the letter subset of the Cyrillic part of the Main code page, apart from the relocation of the uppercase Ё from 0xF0 to 0xA1. ISO-8859-5 is a superset.