I recently purchased a Amcrest ProHD IP2M-841W 1080P camera where the initial configuration is done over some kind of audio signal, a companion app for mobile phones which, at the end of the configuration phase plays a masked "sonar ping"ish sound, barely audible were some kind of clicks and whistles which reminded me of 90s-era dial-up internet.
I've heard this technology is sometimes used in TV ads and similar, paired with malware in phones to track people's viewing habits but I'd never imagined it useful for programming hardware settings into a difficult-to-access device.
I tried researching programming using audio signals, serial and SPI modulators/demodulators and turned up nearly nothing, anything mentioning ultrasound yielded results about ultrasonic depth sensors and CV topics.
What is this technique of programming using audio(& visual?) signals called, and does it require (or benefit from) special hardware, is it reliable, etc?
It seems ideal for first-time configuration of embedded systems, or diagnostics.