Is there any way to route unknown callers (any number not on my contact list) directly to voice mail without ringing my phone? I never answer them; let them ring or swipe left. I have a Gen 1 Moto X with 5.1 Lollipop. Carrier is AT&T.
See if these help: http://www.digitaltrends.com/mobile/how-to-block-phone-calls-on-your-android-smartphone/ https://play.google.com/store/search?q=block unknown calls
If those links from KevinJames don't have what you need, The Asus Dialer & Calling Screen has a number blocking option above the keyboard, and it's really nice. Every number I have put into it has never rang again on my phone, nor have they went to voice mail. My Zenfone 2 runs lollipop.
@palandri: I think what rjniles wants is a method to indiscriminately block all unknown (not in contact list) numbers. @rjniles: It just dawned on me, there is a definite down-side to blocking all unknown numbers. For example, I get calls from Kaiser Permanente's numerous medical & billing offices, very few of which are actually in my contact list. (Their call-in numbers are different from their call-out numbers.) Blocking all unknown calls would jeopardize my receiving important calls.
Kevin James, Thanks for your suggestions. It appears that there is no native method using the phone itself or an Android feature. I did find an app with your second link that seems to be what I want. "Should I answer" is a free app that will let me block any call not in my contact list. But I have found out as you suggest that may not be the wisest move, I was missing calls I need to receive. I turned the blanket block off and now it asks me if I wish to receive the call not on my contact list. I can chose to answer or ignore. If I answer it gives me the option to "blacklist" that caller in the future. I can also blacklist callers on my contact list; this is handy because I have several customers who tie me up with idle chatter. It is better that I force them to leave a voice mail. It also has a feature to block premium and foreign outgoing calls. Thanks again.
This may seem silly and naïve, but have you checked out your call settings? Sometimes it may be buried in there. Sent from my SM-N910V using Tapatalk
Contact your telephone company and inform them that you are getting unknown calls. You may be asked to note the date and the exact time of the calls so it can trace the caller. You may also be asked for your name and phone number. -- Lewis