Windows-1253
Windows code page 1253, commonly known by its IANA-registered name Windows-1253 or abbreviated as cp1253, is a Microsoft Windows code page used to write modern Greek. It is not capable of supporting the older polytonic Greek.
It is not fully compatible with ISO 8859-7 because a few characters, including the letter Ά, are located at different byte values:
µ and ¶ are added at their locations from Windows-1252 and ISO 8859-1. This collides with the locations of ΅ and Ά, respectively, in ISO 8859-7.‘ and ’ are moved from their ISO 8859-7 locations to their Windows-1252 locations. The displaced ΅ and Ά are moved to the vacated space at 0xA1 and 0xA2 respectively.¤ and ¥ are added at their locations from Windows-1252 and ISO 8859-1. This collides with additions made to ISO 8859-7 in 2003, when € and ₯ respectively were added to the same locations. The € was added to Windows-1253 at 0x80, the same location which it was added to in Windows-1252. An iota subscript was also added to ISO 8859-7 at 0xAA; this remains unallocated in Windows-1253.- Several further characters are added at their Windows-1252 locations, although the rest do not collide with ISO 8859-7.
Unicode is preferred for Greek in modern applications, especially as UTF-8 encoding on the Internet. Unicode provides many more glyphs for complete coverage, see Greek alphabet in Unicode and Ancient Greek Musical Notation for tables.