The Jolly Box was originally designed by Jolly Roger and Zaphod Beeblebrox in the early 1990s as the ultimate phone phreaking tool. The portable, battery-powered device was a multi-function, multi-frequency (MF) tone generator specifically used for seizing control of and traversing telephone networks.

The original design consisted of two single-sided circuit boards, one serving as the main CPU board running an Intel 80C39 and the other as the daughter board, which contained an EPROM with stored sound samples for audio generation and a simple D/A converter.

In 1996, while part of L0pht Heavy Industries, Joe Grand (aka Kingpin) made additional hardware and firmware modifications to the Jolly Box, including integrating all circuitry onto one double-sided PCB. He was planning to release the updated design in kit form, but the project was abandoned in October 1996.