JAMMA connector pinout

MVS systems edge connectors aren't fully JAMMA compliant.

The pin pitch is .156in (3.96mm). There are 28 pins per side (key included), 56 total.

Many harnesses don't have the key to avoid accidentally plugging them backwards. Doing so will certainly fry the inputs chip (...).

Note that the G, I, O, and Q letters aren't used, to avoid confusion.

MVS pinout
Infos from [HardMVS.com]