I am suspicious about why someone is calling my number and wanting to know about whether I have security around my home.

somene is calling and not saying anything

This is a telemarketing company for a home alarm system. ?How is it that they don't respect no call lists?  Very irritating especially that they use an automated dialler system which provides dead air when you answer.

this nbr started calling again. No Answer at all.

Calls every day,hangs up before it goes to the last ring prior to the answering machine kicking in.If this is a legitimate call,they should leave a message like everyone else does,however since the calling party wishes not to,I'm left to believe the call is of dubious nature and refuse to answer.

twice today, when i call they hang up