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tors) and were just slightly larger than the telephones they were connected to. They were really nothing more than a device to reproduce the multifrequency sounds that Bell employed. For that reason hardened phreakers often `called them MF-ers - for multifrequency transmitters. (The acronym was also understood to stand for `mother-fuckers`.)

Engineering students have always been notorious for attempts to rip off the phone company. In the late 1950s Bell was making strenuous efforts to stamp out a device that much later was nicknamed the red box - presumably to distinguish it from the blue box. The red box was a primitive gizmo, often no more than an army surplus field telephone or a modified standard phone, linked up to an operating Bell set. Technically very simple, red boxes employed a switch which would send a signal to the local telephone office to indicate the phone had been picked up. But the signal was momentary, just long enough to alert the local office and cause the ringing to stop, but not long enough to send the signal to the telephone office in the city where the call was originated. That was the trick - the billing was set up in the originating office. And to the originating office it would seem as though the phone was still ringing. Legend has it that engineering students would wire up a red box for mom and dad before they left for college so that they could call home free: when pop took his finger off the switch on the box, he and junior could talk.

The red boxes had one serious drawback: the phone company could become suspicious if it found that junior had ostensibly spent a half an hour listening to the phone ring back at the family homestead. A more obvious problem was that mom and pop - if one believes the legend that red boxes were used by college kids to call home - would quickly tire of their role in ripping off the company only to make it easier for junior to call to ask for more money.

There were other boxes, too, all exploiting other holes in the Bell system. A later variation of the original red box, sometimes called a black box, was popular with bookies. It caused the ringing to cease prior to the phone being picked up, thereby preventing the originating office from billing the call. There was also another sort of red box that imitated the sound of coins being dropped into the slot on

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