Perhaps it would even be useful to do networking use audio (like dial up sounds or cassette tapes) One could carefully pick sounds to be the least annoying and have [say] a printer announce to the world that it is still online. One could probably transfer well over 50kb/s but it hardly seems necessary if one rarely prints anything. I already scream at rarely used printers it would be great if it would listen for print jobs. It could take dictation too. Perhaps it is funny to have the entire print order in human speech.<p>Iphones have some weird feature to listen for coughing or water(?) We already have door bells and door knockers sending out audio signals. (Video doorbells are great but knockers are more reliable.) Lots of devices in the home make identifiable sounds. Combined with the security footage you could generate a film of you using your wireless drill, every time you look in the fridge, open the front door, when you shoot someone, etc "vacuum cleaning the movie".<p>The vacuum cleaner can be asked for a status report, its serial, build date etc, how full its bag is utilizing a human friendly machine readable audio signal.<p>It seems much more secure than evil men silently communicating with your devices over the internet.<p>I think we are onto something here.