How did the big guys (eg Midway, Taito etc ) agree on jamma? in my time the big guys tried to sue anyone who put a different game into there boxes (like putting DK into a frogger cabinet).
Pinball Joe
jamma came about because of the big downturn in business in the 80's. they basically all agreed to a standard to cut costs and keep themselves in business.
JAMMA is Japan Amusement Machine and Marketing Association.
Actually it was because all the arcades in Japan switched to candy style cabinets like a pachinko parlor. The operators could then just swap have boards. This was all decided on Japan there there was no downtown in the arcade business.