Telephony 1

Telephone speech sounds like telephone speech because one band, 300 to 3400 Hz, has been held for a century. This volume traces where that band came from, then fixes the choices that follow from it: 8 kHz sampling, 8-bit words, the end-to-end delay budget and the way packet loss makes itself heard. It introduces the quality framework the rest of the series uses — the mean opinion score and the E-model's R factor — so that later volumes can appeal to it without rederiving it.