there are still some mysteries about the Atari C-121 system (offical system of the actual swedish pong championships) which was sold in Europe around 1976-77. althought the company had their own chips they released this system for the european market with a standard rf antenna plug and a common ay-3-8500 chip from general instruments to provide the hockey game that could not be displayed by the atari chip that time. therefore a few technical changes had to be done. the battery compartment (same than those built inside the legendary magnavox 1Tl200 from 1972) for example could take 6x 1,5volt batteries instead of the 4x 1,5volt batteries the atari chips needed. of course the psu plug was changed as well.

the hockey pong was produced in korea and not in the usa like for example atari's first home video game systems the C-100 Pong (that gave the game Pong it´s name) and the C-140 Super Pong.

The strangest thing is, that all Atari Hockey Pongs use the same serial number: 55559E

bottom parts of my speciments.

at least all speciments that i own or owned showed that. is there anybody who has an atari c-121 that has a different serial number please let me know.