We have a wireless doorbell, it's called a dog.
Our neighbours have one of those. So I often know there's a courier approaching before the doorbell/knock sensor goes. I'm also made aware if someone's knocking at any of half a dozen nearby houses, if the neighbours come home or go out, if someone's parking a car outside, if someone puts their bins out, if someone's doing building work, if a pedestrian goes by, or if the dog needs emptying or has been caught chewing something inappropriate.
Barakta, meanwhile (when her hearing aid is in the right mode), is aware that our neighbours have a dog.