Hush-A-Phone Corp. v. United States

However, when an AT&T lawyer saw one in a store window, the company decided to sue on the grounds that anything attached to a phone could damage their network.

The court's decision stated that AT&T's prohibition of the device was not "just, fair, and reasonable," as required under the Communications Act of 1934.

Per the judgment, 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."

Instead, Americans had to connect their modems mechanically by attaching a phone receiver to an acoustic coupler via suction cups.

[3] Regardless, the victory for Hush-A-Phone was widely considered a watershed moment in the development of a secondary market for terminal equipment and the breakup of the Bell System.