[EdFNJ]

Originally Posted by Kenswing

Here's one way.. Amazon.com: CPR V5000 Call Blocker - Block All Robocalls, Scam Calls, Unwanted Calls on Landline Phones. Block All Nuisance Calls at the Touch of A Button. Caller ID Service is Required For This Product To Work: Office Products

That's an excellent device but if you have a possibility of getting any emergency calls from doctors, hospitals, emergency services, from elderly family members in group living or whatever be very wary of sending ALL unknown calls to voicemail. They often use blocked numbers or different numbers at different times of the day or night. My 91yr father was taken to the hospital in the middle of the night a year or so ago and I didn't know about it until until the next morning. I never thought about the downside of blanket call blocking. Fortunately I made it (4hr drive to S.FL) but not with much time to spare.

Those devices will whitelist (pass) specific numbers but that's often not enough under some circumstances.