Traditionally, in the phreakers’ culture, any device thought to be connected to the phone line is called “box” and is named after a color since the first “Blue Box” invented by Captain Crunch, the father of the phreak scene. Since all colors were quickly used for this purpose, other fancyful names were also used to name boxes.
Web link of note: Definitive guide to Phreak Boxes
(At http://www.aboutphone.info/lib/phreak/boxes-2.html)