Some Unicode alt-codes not working

Here is a list of all special Hungarian characters:

ALT-0193 Á   ALT-0225 á
ALT-0201 É   ALT-0233 é
ALT-0205 Í   ALT-0237 í
ALT-0211 Ó   ALT-0214 Ö   ALT-0336 Ő
ALT-0243 ó   ALT-0246 ö   ALT-0337 ő
ALT-0218 Ú   ALT-0220 Ü   ALT+0368 Ű
ALT-0250 ú   ALT-0252 ü   ALT+0369 ű

All are working with Alt+NUMPAD except the third column. I get ordinary P, Q, p and q letters instead of the letters given. What is the reason for this? What code should I input if I want to reach them?

• Windows 7 Enterprise 32-bit
• Reference: http://en.wikipedia.org/wiki/Double_acute_accent

RonK answered the first part of your question. The answer to the second part of your question is, as Microsoft and George Hernandez explain, to type + (on the numeric keypad) and then the hexadecimal value of the Unicode (UCS-16) character, all whilst holding the Alt key down. As George Hernandez writes, this mechanism is not enabled by default, and must be manually enabled after installing Windows.

I don't have it of a certified source - but I think that Alt+Numpad only works for values in the range of 0..255. So everything you try with a higher value is 'cast' down to this range.
So for example: 336-256=80. Due to that -> Alt+336 is the same as Alt+80. Which is 'P'.

Edit: The Alt+Numpad method only works on your active code-page, so it is actually typing characters in your local encoding (e.g. ISO 8859-16 for Hungarian). So basically keying Alt+193 will type a character which is only 1 byte long and has the value 0xC3 (193 in HEX). By coincidence, 193 in ISO 8859-16 has the same display value as \u0193 is the Unicode map. On my local codepage Alt+193 produces the ┴ character which is \u2534 in the unicode map.

My recommendation, if you need to display these values in some application, use the unicode convention instead of keying them in as Alt+Numpad combinations. You can download BableMap for this - it is a great tool for this purpose and is free.