beige box

Short definition from Wiktionary

Noun

1. 1
   A device used in phreaking, technically equivalent to a telephone company lineman's handset: a telephone fitted with alligator clips to attach it to a line.
2. 2
   A desktop computer in the style typical of personal computers of the 1980s and 1990s, having a boxy off-white case and CRT monitor.
3. 3
   An outdated personal computer.