Lawrence looks through a thick glass window into the engineer’s booth, where a phonograph record is playing on the world’s most precise and expensive turntable. This is, likewise, the most valuable record ever turned out: it is filled with what is intended to be perfectly random white noise. The noise is electronically combined with the sound of Lawrence’s voice before it is sent down the wire. Once it gets to London, the noise (which is being read off an identical phonograph record there) is subtracted from his voice, and the result sent into Alan Turing’s headphones. It all depends on the two phonographs being perfectly synchronized. The only way to synchronize them is to transmit that maddening buzzing noise, a carrier wave, along with the voice signal. If all goes well, the opposite phonograph player can lock onto the buzz and spin its wax in lockstep.