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Filtering

Filtering is a general term for systems that automatically block harmful content or unwanted communications. In telephony, it means spam call filters; in internet use, it means web filtering (harmful site blocking).

Web filtering is especially important for minors. Japan's law requires carriers to enable filtering for users under 18 unless parents explicitly opt out.

Two approaches exist: blacklist (blocks known harmful sites) and whitelist (allows only approved sites, blocking everything else). Whitelist is safer but far more restrictive.

Phone filtering matches incoming numbers against nuisance call databases, displaying warnings or auto-blocking. Carrier services and third-party call blocking apps use this mechanism.

Filtering isn't foolproof - newly created harmful sites and unregistered spam numbers can slip through. Combining technical measures with user literacy is essential.

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Related Terms

Spam Call Filter

A feature that automatically identifies potentially nuisance incoming calls and provides warnings or rejection.

Call Blocking

A feature that automatically blocks incoming calls from specific phone numbers or anonymous callers.

Nuisance Call

A general term for unwanted phone calls. Includes sales calls, solicitations, scam calls, and silent calls.

Telecommunications Carrier

A major telecommunications provider that owns its own network infrastructure. Four carriers operate in Japan.

Call Rejection

A feature that automatically blocks incoming calls from specific numbers or withheld numbers. A fundamental defense against nuisance calls.

Spam

Unsolicited bulk communications including calls, SMS, and emails, often sent via automated dialing systems.

Related Articles

Keeping Children Safe - Smartphone and Phone Number Security for KidsHow to Choose a Spam Call Blocker App - Free vs Paid Options ComparedHow to Fight Nuisance Calls - From Call Blocking to Reporting
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