TitleTelephone "Blue Box"
Dimensionsoverall: 2 1/2 in x 6 1/4 in x 3 3/4 in
DescriptionThe object consists of a black plastic box with a black plastic cover containing logic elements, two batteries, and on the cover a white switch. The cover has eleven red push buttons. There is also a telephone jack for output. There is a square of paper taped to the cover that has four rows of numbers, which are written in pencil.
In two issues of the Bell System Technical Journal, one in 1954, the other in 1960, the company published articles that listed the frequencies used internally by the phone company to control the billing of telephone calls. This laid bare a weakness of the telephone system at the time, namely in-band signaling, in which signals used to control the flow and billing of a call could actually be heard (or generated) by a caller. Building “Blue Boxes” to generate these tones became mainstream when these earlier Bell articles were cited in a 1971 Esquire article.
Among the people who noticed were two California teenagers, Steven Jobs and Stephen Wozniak. The “two Steves” built so-called “Blue Boxes” and sold them publicly. Building Blue Boxes taught the pair about product assembly and sales. “Without the Blue Box,” Steve Jobs once said, “there would be no Apple.”