Telecommunications & OSINT Technical Glossary

STIR/SHAKEN Framework
Secure Telephone Identity Revisited (STIR) and Signature-based Handling of Asserted information Using tokens (SHAKEN). A suite of protocols used by carriers to authenticate caller ID and combat spoofing.
E.164 International Format
The international telecommunication numbering plan that defines format structure: [Country Code] [Area/Destination Code] [Subscriber Number] up to 15 digits.
CNAM (Calling Name Delivery)
A database service queried by receiving telecom switches to resolve a 15-character subscriber name associated with an incoming phone number.
HLR (Home Location Register)
A central database containing details of authorized SIM cards registered on a mobile network, validating real-time carrier status and roaming location.
DND (Do Not Disturb) Registry
National regulatory databases (e.g. TRAI India DND, US FTC National Do Not Call) where subscribers register to block unsolicited commercial communications.

Caller ID & Lookup Solution Comparison

Feature / Metric WhoCalled Web WhoCalled Telegram Bot Legacy Caller ID Apps
Address Book Upload ❌ Never Required ❌ Zero Access ⚠️ Mandatory Harvest
Search Latency < 30 ms (Redis In-Memory) Instant (Telegram API) 1.5 - 3.0 seconds
Database Shard Capacity 1.78 Billion Records 1.78 Billion Records Proprietary / Masked
App Installation Browser Native No App Needed (Telegram) Heavy Mobile App

Unknown Call Handling Flowchart

📞 Incoming Call from Unknown Number
↓
Query Number on WhoCalled Web or @AdvanceTruecallerBot
↓
Verified / Trusted Caller
Answer call or reply via official channels.
High Spam / Scam Rating
Do not answer, do not share OTP, and block number.
🤖 Telegram Bot Page | 🌐 Web Search

Spam Detection & Robocall Risk Shield Hub

WhoCalled.in analyzes millions of daily lookup events, user reports, and automated calling patterns to calculate real-time Spam Threat Ratings for phone numbers across 150+ countries.

Spam Scoring Categories

🚨 High Risk Financial Scams

Impersonation of banking officers, OTP phishing, fake credit card reward offers, and UPI payment scams.

📞 Automated Robocalls

Pre-recorded telemarketing broadcasts, automated debt collection systems, and survey bots.

⚠️ Unsolicited Telemarketing

Unregistered promotional callers violating national Do Not Disturb (DND) regulatory registries.

Explore Spam Prevention Pillar Guides

Check a Suspicious Number Now

Instantly check any unknown number for spam reports using our official Telegram Bot:

🚨 Check Spam via @AdvanceTruecallerBot

Research Methodology, Search Accuracy & Privacy Transparency

🔬 How WhoCalled.in Search Works

WhoCalled.in aggregates cross-verified data signals from national telecom routing tables, Home Location Register (HLR) status dips, public OSINT records, and community spam reporting. Search queries do not inspect personal devices or contact books.

📊 Search Accuracy & Confidence Scores

🔒 Strict Data Privacy Guarantee

WhoCalled.in strictly adheres to global privacy frameworks (GDPR, CCPA, and TRAI DND regulations). We never request, upload, or harvest user contact lists. Individual subscribers can submit opt-out requests at any time via our Privacy Opt-Out Portal.

📝 Editorial Standards & Update History

Our telecommunications research guides are continuously audited by information retrieval engineers. Database indexes are synchronized daily (Last Verified: July 29, 2026).

System Capabilities & Technical Limitations Disclosure

⚠️ What WhoCalled.in CANNOT Determine

To maintain complete transparency and technical accuracy, users should be aware of technical boundaries inherent to public telecommunications databases:

Enterprise Governance & Privacy Protection: WhoCalled.in provides privacy, correction, and data-removal channels for its caller lookup service. Contact our Data Protection Officer at dpo@whocalled.in for data verification or opt-out requests.

Index Last Reviewed & Updated: July 29, 2026 | Caller Lookup Resources