CusCo
From Futurepedia, the Back to the Future Wiki
CusCo was a company in Hill Valley located at 11249 Business Center Road. Ito T. Fujitsu was a supervisor at the plant, with Marty McFly and Douglas J. Needles working for him.
Needles called Marty to perform an illegal action that would turn profit for him, but "The Jitz" was monitoring and subsequently fired Marty from his job, and sent a fax with the words "You're fired!!!" on company letterhead.
When his mother saw the fax that Fujitsu sent, Marty tried to claim it was a joke.
[edit] Behind the scenes
On the fax, the zip code for Hill Valley, California, is given as 95420. In real life, 95420 is the zip code for Caspar, California, a town on the Pacific coast in Northern California.
