Pinout for a 6 pin 3x4 keypad
Figuring out the pinout of a simple matrix keypad is pretty simple: identify (number) the connector pins, then make a table of which connector pins become shorted as each key is pressed.

Your 6-pin connector has 1- square pad at one end with the remaining pads being round.  The normal convention is that the odd pin out is #1 so let's call that square pad pin #1.

Now simply follow each key's traces to the connector pads and make your table.

For example:

(1) is pins 1, 2

(2) is pins 2, 6

(3) is pins 2, 5

Etc.

It looks as if this is a fairly non-standard matrix in that the rows / columns have 5 keys each instead of 3 &amp; 4.  This allows the designer to get away with using only 6 pins on the connector instead of 7 pins.

That's okay - the principles or reading the keypad remain the same: set one row active (the remaining rows non-active), then see which of the columns also became active.