I was wondering the same. The picture accompanying that text was a plate from a Vibroplex Bug, a semiautomatic telegraph key. https://infostory.com/2013/08/27/

I was wondering the same. The picture accompanying that text was a plate from a Vibroplex Bug, a semiautomatic telegraph key. https://infostory.com/2013/08/27/debugging-the-origin-of-the-term-bug/ https://infostory.com/2013/08/27/debugging-the-origin-of-the... talks a bit more about the bug trap and the false signals.