Converting the symbol 'º' gives 'C2BA', but this is an iso-8859-1 encoded file, so the output should be 1 byte long.

Octadecimal is not the same as Octal. Octadecimal is similar to Hexadecimal but with two more digits.

When you convert Hex : \n(0A) to ASCII it gets removed.
The new line should remain as it is.

what about add this new functionality to plugin?

     Unicode -> Hex
     Hex -> Unicode
     UTF-8 -> Hex
     Hex -> UTF-8

or probably best solution is look at the document setting (ANSI, UTF-8, Unicode...) and do it automatically, just change caption in menu universally:

     Text -> Hex
     Hex -> Text

keep text conversion on user if he need different format

now it is possible to convert only:
ASCII -> HEX
HEX -> ASCII

please add new conversion options
HEX -> BIN (binary)
BIN -> HEX
ASCII -> BIN
BIN-> ASCII

I sometimes need to convert data directly from the collected binary 1 and 0.
An example of working with binary data:
01100001 01100010 01100011 -> abc
abc -> 01100001 01100010 01100011

This issue has been raised in the notepad-plus-plus repository here. It looks like Scintilla returns the highlighted NUL text as a space. See here

I've experienced some problems with the ASCII -> HEX conversion that is a bit ODD on 64-bit version of Notepad++.

The NUL character (hex 00) will convert to hex 20 instead of 00, and if the ASCII string contains the (hex FF) character the conversion will NOT occur.

I think these may be a result of the recent changes for the following version:
Notepad++ v7.3.3 (64-bit)
Build time : Mar 8 2017 - 03:39:58
Path : C:\Program Files\Notepad++\notepad++.exe
Admin mode : OFF
Local Conf mode : OFF
OS : Windows 10 (64-bit)
Plugins : mimeTools.dll NppConverter.dll

NOTE: If I change the 20 hex values back to 00 then the conversion from HEX -> ASCII is correct for the NUL character.

I convert ff from hex to ascii and get xFF
Then I try to convert xFF back to hex but nothing happens.
Is this a bug?
Best
Hakan Toptas, Istanbul

Sorry did not see the similar issue.

Pasting/Writing hexadecimal numbers in the conversion panel in the form of 0x7f0d0336 instead of just 7f0d0336 should be possible.

Steps to reproduce:

1. Open the conversion panel using Plugins -> Converter -> Conversion Panel
2. Enter a hexadecimal value of 200b
3. Click copy or insert for ASCII

Expected result

That a ZERO LENGTH SPACE would be copied into the clipboard when Copy was clicked or inserted into the document when Insert was clicked.

Actual result

Nothing.

The clipboard maintains previous contents and no new characters are added to the document.

Version 4.4 doesn't convert ASCII(xFF) to Hex (in NPP v8.4.2 (64-bit))

Exemple:

Hex -> Dec
1AB3F00 -> 28000000

Dec -> Hex
28000000 -> 1AB3F00