The Hush-a-phone was a device that snapped on to a telephone and made it possible for the user to speak in a whisper. The FCC banned the device, following a long-standing policy of prohibiting any device that attached to the telephone system to which AT&T objected.
Tom Carter, the developer of the Hush-a-phone took the ban to court, and in 1956 the D.C. Circuit Court of Appeals overruled the FCC and held that the device could to be sold and used. The court found that AT&T's prohibition of the device was not "just, fair, and reasonable," as required under the Communications Act of 1934, since the device "does not physically impair any of the facilities of the telephone companies," nor did it "affect more than the conversation of the user."