AI Detection for Narrowband (8 kHz μ-law) Telephony Spam and Spoof-Call Blocking
A survey of AI methods for detecting spam and spoofed calls on narrowband 8 kHz μ-law (G.711) telephony. No published anti-spoofing equal-error-rate is measured on native 8 kHz audio, and the best acoustic results do not transfer to narrowband or to the dominant attack: voice changers on genuine voice. The defensible architecture is emergent from layer composition: a Boolean core of behavioral metadata plus STIR/SHAKEN, with acoustic detection demoted to a post-call signal.