In my digital logic lecture today, my professor introduced a symbol code called Patty Code. I copied this table off the whiteboard:

     | Symbol | Binary | Odd Patty | Even Patty |
     | a      |     00 |       100 | 000        |
     | b      |     01 |       001 | 101        |
     | c      |     10 |       010 | 110        |
     | d      |     11 |       111 | 011        |

I did try Googling for both "patty code" and "patti code" with nothing substantial.

I asked my professor after lecture what is Patty Code. He said it's used occasionally. I asked him if it's another name for excess-3 or grey code, to which he said it is different to both of those codes.

Is my professor yanking my class's chain, or is this actually a real code?


I want to leave record that the professor that gave me this misconception has a relatively strong accent. He is very knowledgeable and always gives me a satisfactory answer to EE related questions. So I finished that class, and am happy with the result. Hopefully nobody else has to Google this question!

  • 8
    \$\begingroup\$ I've heard of party code like bring a bottle etc.. \$\endgroup\$
    – Andy aka
    Jan 31, 2017 at 17:45
  • 1
    \$\begingroup\$ @MatthewWhited Change the instructor because of handwriting? Really? I hope you don't take this approach when choosing a doctor.. \$\endgroup\$
    – Eugene Sh.
    Jan 31, 2017 at 18:54
  • 6
    \$\begingroup\$ Yes, he doesn’t have the required skills to be instructing if people cannot understand him. \$\endgroup\$ Jan 31, 2017 at 18:56
  • 4
    \$\begingroup\$ Next lecture I'll ask him if he means parity code, and refer to the text :) \$\endgroup\$
    – Winny
    Jan 31, 2017 at 19:04
  • 2
    \$\begingroup\$ In the Netherlands, we have a celebrity called Patty and she is odd for different reasons. Just wonder who is the even Patty. \$\endgroup\$ Feb 1, 2017 at 21:53

3 Answers 3


Parity. The word is Parity. Hopefully it was just misheard.

  • 4
    \$\begingroup\$ @Winny I removed the comments as I've realized that I haven't recognized the encoding correctly. It is parity bit though, not parity code. I assume it's your prof handwriting issue.. \$\endgroup\$
    – Eugene Sh.
    Jan 31, 2017 at 17:41
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    \$\begingroup\$ Patty Code, Patty Code, EE man; Adding up bits, As fast as you can; To even or odd, Mark it with a bit; And you stop bad data glitches and won't have a fit! \$\endgroup\$ Jan 31, 2017 at 21:30
  • 14
    \$\begingroup\$ Once there was a pirate captain whose shoulder-bird would often whistle and squawk out "Pieces of nine! Pieces of nine!" Turns out it was a parroty error. \$\endgroup\$ Feb 1, 2017 at 16:17
  • 1
    \$\begingroup\$ I had a calculus professor pronounce a Greek letter "btheda". And he drew something that looked like ó, but connected. I went and found a greek alphabet online and discovered it was δ - a lower case delta. Of course that's much better than my Operating Systems professor who was talking about forking child process, but her accent made her say, "... fook a child process." It was even worse when everyone started laughing and she tried even harder, but still pronounced it the same. \$\endgroup\$ Feb 1, 2017 at 21:20
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    \$\begingroup\$ @Winny: Sometimes, people transcribe their accent. Or you get second generation usage by someone who learned it from someone who had it wrong. \$\endgroup\$
    – user90235
    Feb 1, 2017 at 23:36

Yes, it's "parity". The code adds a third bit to make the number of ones either even or odd:

00 -> 100 = 1 one = odd
01 -> 001 = 1 one = odd
10 -> 010 = 1 one = odd
11 -> 111 = 3 ones = odd

00 -> 000 = 0 ones = even
01 -> 101 = 2 ones = even
10 -> 110 = 2 ones = even
11 -> 011 = 2 ones = even

this is called parity code and the last bit is adding each time is called parity bit. for example:

last bit of even and odd is parity bit like if u have 0000000 then odd parity will be 00000001 and even parity will be 00000000. another example..if you have 1101001 then even parity will be 11010010 and odd parity will be 11010011 . it's based on count of 1. if count of 1 in the given bit is even then in even parity 0 will be added as a parity bit and 1 will be added in case of odd parity...and it will alter if number of 1 is odd in the given bit

hope you got your answer...and there's nothing like patty bit. and from your table i am pretty sure that it is parity not patty


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