LineLayer Learn

Learn about call privacy.

Practical guides about phone numbers, Android permissions, caller ID, unwanted calls, and protecting your contact data.

Currently covering Call Privacy · Android · Caller ID · Guides.

Also on LineLayer Learn: check a number against recent FTC and FCC reports, or learn how LineLayer controls incoming calls on Android.

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Guides 8 min read

How to Block Calls From Numbers Not in Your Contacts on Android

Learn how to block calls from numbers not in your contacts on Android, including Google Phone, Pixel, Samsung Galaxy, and call-screening options.
Android 7 min read

Why Blocking “Unknown Calls” on Android May Not Do What You Think

On Phone by Google, “Unknown” blocks private or unidentified callers—not every number outside your contacts. See Pixel and Samsung differences.
Call Privacy 8 min read

Phone Scam Statistics 2026: How Much Are Scam Calls Really Costing People?

Latest U.S. phone scam statistics for 2026, including FTC complaints, FBI losses, robocalls, spoofing, and what the numbers really measure.
Caller ID 7 min read

Private, Hidden and Unknown Calls: What’s the Difference?

Private, hidden, unknown, not-in-contacts, spam, and spoofed calls are not the same. Learn what each label means and how Android treats them.
Android 8 min read

What Happens When an Android App Gets Access to Your Contacts?

Learn what Android’s READ_CONTACTS permission actually allows, what it does not prove, and how to evaluate an app that asks for contact access.