Windows-1253 is a 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 the letters like Ά are located at different byte values.
Unicode is preferred for modern applications.
Code page layout
The following table shows Windows-1253. Each character is shown with its Unicode equivalent and its decimal code.
Legend:
References
Windows-1253 Wikipedia(Text) CC BY-SA