Answered the call and got no answer. What's this about? Trying to see if we are home?

Just got a call from this number I heard a lot of noise in the background and someone was obviously there but hung up when I said hello. Tried calling it back and I get the recording that the number isn't valid. What????

2 rings then hung up ?

Same here, Mongoose - a couple rings then they hung up.

Sometimes I will answer calls that have Area Codes within our range or nearby - but I have a headache and didn't feel like hearing anything or speaking to anyone.

Same thing here. I live in 925 area code so thought I should answer. Says Name Unavailable.  someone definitely on other end as like some others on here, there's noise like someone is there but with a noisy environment.  Said hello a couple of times and caller eventually just hangs up.