Neo Geo:Connector Pinouts

Originally from Neo Geo Dev wiki, provided here for convenience.

JAMMA Edge

Top	Pin		Pin	Bottom
GND	1		A	GND
GND	2		B	GND
+5V	3		C	+5V
+5V	4		D	+5V
Unused	5		E	Unused
+12V	6		F	+12V
Key	7		H	Key
Coin counter 1	8		J	Coin counter 2
Coin lockout 1	9		K	Coin lockout 2
Audio Right	10		L	Audio Left
Mono audio out	11		M	Test button
Video Red	12		N	Video Green
Video Blue	13		P	Video Sync
Video GND	14		R	Service button
Coin #3 (P1)	15		S	Coin #4 (P2)
Coin #1 (P1)	16		T	Coin #2 (P2)
Start	17		U	Start
Up	18		V	Up
Down	19		W	Down
Left	20		X	Left
Right	21		Y	Right
Button A	22		Z	Button A
Button B	23		a	Button B
Button C	24		b	Button C
Button D	25		c	Button D
Select	26		d	Select
GND	27		e	GND
GND	28		f	GND