If you're on Android, you can whitelist inbound calls using a freemium app called Mr. Number[1]. I'm not sure there's anything even remotely like it on iOS. If

If you're on Android, you can whitelist inbound calls using a freemium app called Mr. Number[1]. I'm not sure there's anything even remotely like it on iOS. If you're using a VOIP service, ymmv. Before I switched to Ooma, my previous VOIP provider allowed you have a whitelist. So basically anyone not in my contacts got bounced to voicemail, and my phone would not ring at all. Ooma's call blocking is obtuse and manual, but it's half the price of my last provider, and the call quality is way better. An unfortunate compromise, I guess. As for land lines, I used to use a now discontinued device+software called a Phone Valet [2] connected to an unused Mac. It basically acted as an answering machine/lightweight IVR. My phone would ring once so that the caller ID could get picked up by the device, and then based on a set of rules, my phone would either continue ringing, hang up (on known telemarketer numbers) or redirect to voicemail (everyone else). It was a pretty neat device, but I guess the decline of the landline led that product to be EOL'ed. [1] http://mrnumber.com/ http://mrnumber.com/ [2] http://www.phonevalet.com/ http://www.phonevalet.com/