The JAMMA Connector!  Copied from [[http://www.gamesx.com/arcade/jamma.htm|the old page]]

This is a standard in the arcade industry. Starting sometime in the late eighties, the [[http://www.jamma.or.jp/english/|Japanese Amusement Machine Manufacturers Association]] set about making a standardized game interface. This would alleviate the silliness of rewiring a cab for every new game was installed. Most games required the same inputs: one or two 4-way joysticks, 1-4 buttons for each player, coin inputs, start button, etc. 

With the JAMMA connector almost every game produced that didn't involve a deluxe cabinet (ie AfterBurner or Virtua Racing) any JAMMA game can be shoved into a cabinet which previously held any other JAMMA game.  There are caveats - a lot of games deviated from the specification, and sometimes things like stereo sound, analogue controls and other features were added, or inputs moved around.  As a rule though, power and video were locked in place so you'll rarely, if ever, damage one JAMMA board by plugging it in where another was used.

Roughly speaking there are only five things to connect to the game board through the wiring harness: player 1 & 2 controls, the monitor output, sound, power input and the coin-door's switches. These signals are usually grouped together.  The diagram below shows the most common JAMMA pinout, and how these connections are made to the game board. 



^  PARTS SIDE  ^^  SOLDER SIDE  ^^
|  GND |  1  |  A  | GND  |
|  GND |  2  |  B  | GND  |
|  <color yellow>+5V</color> |  3  |  C  | <color yellow>+5V</color>  |
|  <color yellow>-5V</color> |  4  |  D  | <color yellow>+5V</color>  |
|  <color yellow>-5V</color> |  5  |  E  | <color yellow>-5V</color>  |
|  <color yellow>+12V</color> |  6  |  F  | <color yellow>+12V</color>  |
|  KEY |  7  |  H  | KEY  |
|  <color pink>COUNTER 1</color> |  8  |  J  | <color pink>COUNTER 2</color>  |
|  <color pink>COIN LOCKOUT 1</color> |  9  |  K  | <color pink>COIN LOCKOUT 2</color> |
|  SPEAKER + |  10  |  L  | SPEAKER -  |
|  N/C |  11  |  M  | N/C  |
|  <color #44ff44>RED</color> |  12  |  N  | <color #44ff44>GREEN</color>  |
|  <color #44ff44>BLUE</color> |  13  |  P  | <color #44ff44>SYNC</color>  |
|  <color #44ff44>GND</color> |  14  |  R  | <color pink>SERVICE SW</color>  |
|  <color pink>TEST SW</color> |  15  |  S  | <color pink>SLAM SW</color>  |
|  <color pink>COIN 1</color> |  16  |  T  | <color pink>COIN 2</color>  |
|  <color #ffbb00>1P START</color> |  17  |  U  | <color #ff7700>2P START</color>  |
|  <color #ffbb00>1P UP</color> |  18  |  V  | <color #ff7700>2P UP</color>  |
|  <color #ffbb00>1P DOWN</color> |  19  |  W  | <color #ff7700>2P DOWN</color>  |
|  <color #ffbb00>1P LEFT</color> |  20  |  X  | <color #ff7700>2P LEFT</color>  |
|  <color #ffbb00>1P RIGHT</color> |  21  |  Y  | <color #ff7700>2P RIGHT</color>  |
|  <color #ffbb00>1P FIRE 1</color> |  22  |  Z  | <color #ff7700>2P FIRE 1</color>  |
|  <color #ffbb00>1P FIRE 2</color> |  23  |  z  | <color #ff7700>2P FIRE 2</color>  |
|  <color #ffbb00>1P FIRE 3</color> |  24  |  b  | <color #ff7700>2P FIRE 3</color>  |
|  <color #ffbb00>(Fire 4) N/C</color> |  25  |  c  | <color #ff7700>N/C (Fire 4)</color>  |
|  N/C |  26  |  d  | N/C  |
|  GND |  27  |  e  | GND  |
|  GND |  28  |  f  | GND  |

<color yellow>POWER</color> \\
<color #44ff44>Video output</color> \\ 
<color pink>Coin door signals</color> \\
<color #ffbb00>Player 1 controls</color> \\ 
<color #ff7700>Player 2 controls</color> \\