with enough a sense of everyone-knows-that

In the old days science fiction writers felt obliged to explain the far-out technologies they invented:

"You know, of course, my dear Throckmorton, that when you move that lever to the upper position it completes an electrical circuit that allows current to flow through a thread in the evacuated bulb, causing it to glow with the light that has replaced the gas flame of your parents."

Modern readers of science-fiction have become better able to fill in the gaps themselves:

"He slipped the cube in the upreader of his comppack and reviewed the case."

This is not to suggest that von Eck phreaking is not presently tchnologically possible, merely that one need not infer its present existence from casual mentions in a Neal Stephenson novel.