How to protect yourself against robocalls:

Here are some steps you can take to try to block unwanted robocalls and telemarketing calls. Sign up your landline and mobile phone on the National Do Not Call Registry at donotcall.gov. Yes, Sen. Blumenthal called it ineffectual against telemarketers that ignore state and federal laws, but many legitimate companies try to operate within the law, and using the Do Not Call Registry should reduce the number of unwanted calls.

Install call-blocking apps. The National Consumer Law Center suggests call-blocking apps YouMail and Nomorobo, which provide free or low-cost services to filter out identified robocallers and enable smartphone users to block specific numbers and report the calls. But they don’t work on landlines and, for reasons detailed in the next tip, might not be as effective on iPhones. Yet the iPhone app store offers numerous highly rated apps, including RoboKiller and Mr. Number.

Trade your iPhone in for an Android phone. A deal-breaker for iPhone lovers, for sure, but YouMail, maker of a free robocall-blocking phone app, recently reported that iPhones receive 29 percent more robocalls than Android phones. The reasons have to do with differences in the ways the phones’ operating systems process “blacklists” of numbers that shouldn’t connect and “whitelists” of approved numbers when call-blocking software is installed.

Revoke consent. “If you are receiving robocalls from a bank, lender or other company you do business with, they likely have your consent hidden in the fine print,” according to the National Consumer Law Center. “While they like having that option, it isn’t their right and you can revoke your consent at any time.” The center advises consumers to contact customer service and add your number to their “do not call” list.

Don’t engage with the caller. If prompted by a robocaller to press a key or give a voice command, don’t. Even if the recording tells you pressing a key will put you on a “do not call” list, it actually lets the caller know your number is active and you will likely answer future calls. Some fraud fighters say speaking the word “yes” in response to prompts can give fraudsters the ability to fake your consent for future goods and services. Don’t answer unknown numbers. The law center says this should be a last resort, because unknown numbers can be important calls. Most legitimate callers, however, will leave voicemail messages.