By default, the numeric keypad way of entering characters by code can only access the first 256 characters. (I believe these are defined by your system's code page for non-Unicode programs.) Codes bigger than 256 get wrapped around, so code 257 actually gets you character 1.
To enable the entry of all Unicode characters by code, create a string registry value in Computer\HKEY_CURRENT_USER\Control Panel\Input Method
called EnableHexNumpad
with the value of 1
. Then you'll be able to enter any character by holding down the right Alt key, pressing the + button on the numeric keypad, entering the hex code (2, 7, 1, 3 in your case), and releasing the Alt key. You may need to log off and back on before this input type is enabled.
Note that the non-+ method of entering ASCII characters by code will continue to wrap around even after you enable this mode.