Apple, Google, and carrier tools: what they can and cannot do

Both kinds of screening errors matter

• False negative: a scam or unwanted call is allowed through.
• False positive: a wanted call from an unfamiliar number is labeled, filtered, or blocked.

Why are false positives a real household problem?

Important organizations often call from rotating or unfamiliar numbers: a medical office, hospital, lab, pharmacy, care team, scheduling desk, prior authorization service, school, insurer, home-repair provider, or delivery company. A number may also be labeled from high-volume reputation data even when the call matters to you. Save known contacts, but plan for the calls that cannot be saved in advance.

STIR/SHAKEN can help a carrier show whether the calling number was authenticated in transit. It helps with caller-ID spoofing, but it does not prove a caller is legitimate, trustworthy, or the organization they claim to be. A signed call can still be unwanted or fraudulent. An “A” attestation is still the signing provider’s own claim, and providers have been held to account for getting it wrong. In 2024 the FCC settled with Lingo Telecom ($1 million) after A-level attestations were applied to spoofed AI robocalls based largely on a customer certification (DA-24-790). More detail: caller ID spoofing and STIR/SHAKEN limits.

More than one layer can affect the same call

Caller → originating carrier → STIR/SHAKEN → terminating carrier → reputation analytics → carrier filtering product → Apple/Google screening → third-party apps → user

What can Apple iPhone screening do?

Recent iPhones can screen or silence unknown callers and filter calls identified as spam. Apple advises saving important people and organizations in Contacts so their calls remain visible. Review the Apple guide to screening and blocking calls for the options available on your device. Live Voicemail can give you another choice: listen as a caller leaves a message and decide whether to pick up when the call is legitimate.

What can Android and the Phone by Google app do?

The Phone by Google app can show caller ID and spam warnings, filter reported spam, and on eligible devices offer Call Screen. Google says features vary by device and region; its Call Screen guide also notes that not all spam and robocalls can be detected. Read Google’s Call Screen instructions and caller ID and spam-protection guidance before enabling a stronger setting.

What do U.S. carrier call-filtering layers do?

Major U.S. carriers offer their own call-labeling or blocking tools. These carrier layers can sit alongside Apple or Google options, so check which setting is doing what before turning on more than one aggressive filter. Their options, availability, pricing, and privacy practices differ, so use your carrier’s current information rather than relying on a name on your screen.

• AT&T robocall and ActiveArmor support
• T-Mobile Scam Shield
• Verizon Call Filter

A safer setup and recovery routine

1. Save family, school, care-team, pharmacy, work, and regularly used service-provider numbers.
2. Begin with labels or manual screening before automatic blocking. Make one change at a time so you know where a call was filtered.
3. After a setting change, make a test call from an unsaved number and check voicemail, recent calls, spam folders, and carrier filtered-call lists.
4. Tell medical offices and other essential services to leave a clear voicemail with a direct callback number. Agree on a manual screening routine for urgent calls.
5. If a filtered medical call is discovered, recover by checking the phone and carrier lists, calling the provider through its official number, and dialing back the aggressive setting until you understand the trade-off.

We think you should not have to choose

BlockTheCalls is designed around a different idea: for screened incoming calls, let an unfamiliar caller say who they are and why they are calling before the subscriber decides whether to take the call. That creates friction for unwanted callers without claiming that any system is perfect.

Our goal: block more bad calls while giving real callers a clear path through.

For broader privacy and scam-response steps, see our Privacy Guide for U.S. households. For federal guidance on the difference between blocking and labeling, see the FTC’s guide to blocking unwanted calls.