Cryptonomicon

by Neal Stephenson

KDD, like many other PTTs around the world, has tried to crack down on callback services by compiling lists of the callback numbers and blocking calls to those numbers. When I talked to Eric Doescher, ITL’s director of marketing, I expected him to be outraged about such attacks. But it soon became evident that if he ever felt that way, he long ago got over it and now views all such efforts with jaded amusement. “In Uganda,” he said, “the PTT blocked all calls to the 206 area code. So we issued numbers from different area codes. In Saudi Arabia, they disabled touch-tones upon connection so our users were unable to place calls when the callback arrived — so we instituted a sophisticated voice recognition system — customer service reps who listened to our customers speaking the number and keyed it into the system.” In Canada, a bizarre situation developed in which calls from the Yukon and Northwest Territories to the big southeastern cities like Ottawa and Toronto were actually cheaper — by a factor of three — when routed through Seattle than when dialed directly. In response to the flood of Kallback traffic, Canada’s Northern Telecom had human operators monitor phone calls, listening for the distinctive pattern of a trigger call: one ring followed by a hang-up. They then blocked calls to those numbers. So ITL substituted a busy signal for the ringing sound. Northern Telecom, unwilling to block calls to every phone in the US that was ever busy, was checkmated.