Vertical Hex Mode is enabled by pressing Alt+J (or selecting Text + Vertical Hex from the View menu). Vertical Hex mode looks as follows:

 

 

 

The file is displayed one line at a time (just as in text mode). However, each line is followed by 2 lines containing the hex code of each character in the line.

 

The 2 lines need to be read vertically. That is, the first line contains the first nibble (4 bits) of the code and the second line contains the second nibble.

 

In the example above, the first character in line 1 is ZERO, which is 30 in hex. Therefore, the first character in line 2 is 3 and the first character in line 3 is 0.