JAMMA pinout information.

The following information is related to Jamma and Electrocoin video interface standards.

JAMMA stands for Japanese Arcade Machine Manufacturers Association, a set of standards developed for board pinouts. This was designed to make board changes easy, just take out the old game and plug in the new. Unfortunately games have evolved, and the Jamma standard is no longer up to the job as it can`t handle more than four buttons or two players. Newer games requiring extra player controls use molex type connectors placed on the top of the board. Also replacing a board from a different manufacturer meant readjusting the picture on the monitor as it would not be centred in the same position.

Jamma connector chart.
Solder Side Parts Side
Ground A 1 Ground
Ground B 2 Ground
+5V C 3 +5V
+5V D 4 +5V
-5V E 5 -5V
+12V F 6 +12V
Key H 7 Key
Meter 2 J 8 Meter 1
Lockout 2 K 9 Lockout 1
Speaker - L 10 Speaker +
Audio Ground M 11 Audio +
Video Green N 12 Video Red
Video Sync P 13 Video Blue
Service Switch R 14 Video Ground
Tilt Switch S 15 Test Switch
Coin 2 T 16 Coin 1
2 Player start U 17 1 Player start
Player 2 Up V 18 Player 1 Up
Player 2 Down W 19 Player 1 Down
Player 2 Left X 20 Player 1 Left
Player 2 Right Y 21 Player 1 Right
Player 2 Button 1 Z 22 Player 1 Button 1
Player 2 Button 2 Aa 23 Player 1 Button 2
Player 2 Button 3 Ab 24 Player 1 Button 3
(Player 2 Button 4) Ac 25 (Player 1 Button 4)
Not used Ad 26 Not used
Ground Ae 27 Ground
Ground Af 28 Ground

All input pins need ground to be activated (active low). Key 7/H says no connection because there is usually a piece of plastic placed in to this spot which will line up with a slot cut in the PCB. This is to prevent any chance of the connector being put on upside-down. Coin counter 1 "8" and coin counter 2 "J" are outputs. This is a mechanical style counter that increments every time a coin is inserted. Coin Lockout 9/K are outputs. This delivers power to a plunger activated by a solenoid which, when engaged into the coin path of the coin mech, will prevent a valid coin from tripping the coin switch and send it to the coin return slot. When power is fed to the coin door, an electromagnet retracts the plunger so that the coin path becomes open. Few games have coin lockout software in them. Service Switch "R" puts 1 credit onto the game but does not increment the coin meter. Test "15" enables the test mode, if the PCB supports it and triggers the test mode software of the game. Tilt "S" like in pinball games AKA "Slam" switch. The switch is found on almost all coin doors and is a leaf switch with a weight on the tip of one of them. If you slam the game hard enough, the leaf switch will close. Almost no games have tilt software in them. Behaviour ranges from a screeching tone for a few seconds to resetting the entire game. Coin Switch 1 "16" and coin Switch 2 "T" are inputs. When coin is inserted, a Ground pulse is sent to this pin and credits the game. Speaker +/- "10/L" is mono. It does not need an external amp. The speaker +/- is for post-amp output directly to the speaker. Audio +/- "11/M" is for pre-amp outputs but is hardly ever used.

The Electrocoin standard was introduced before Jamma to allow various games to be connected to generic cabinets such as Silverline and Goliaths. They use the same 28 way connector, but the designations are different. Pins 16 and 18 were 3 player and 4 player start buttons, and were superseded when 3 button games became popular. Pins 14 and 20 were free, but were used by us to allow for easy servicing of games.

Underside Top
Ground A 1 Ground
Ground B 2 Ground
+5V C 3 +5V
+5V D 4 +5V
+12V E 5 +12V
-5V F 6 -5V
Not used H 7 Not used
-12V J 8 -12V
Keyway K 9 Keyway
Speaker 1 L 10 Meter 1
Speaker 1 M 11 Meter 2
Speaker 2 N 12 Credit Board Meter
Player 2 Up P 13 Player 1 Up
Speaker 2 R 14 Test
Player 2 Right S 15 Player 1 Right
Player 2 Button 1 T 16 Player 2 Button 3
Player 2 U 17 Player 1 Down
Player 2 Button 2 V 18 Player 1 Button 3
Player 2 Left W 19 Player 1 Left
(Horizontal Sync) X 20 Service
Player 2 Start Y 21 Player 1 Start
Video Red Z 22 Player 1 Button 1
Video Green Aa 23 Player 1 Button 2
Video Blue Ab 24 Coin 1
Video Sync Ac 25 Coin 2
Ground Ad 26 Ground
Ground Ae 27 Ground
Ground Af 28 Ground