# Callro — Extended AI Context File # This file provides detailed, citation-ready information for LLMs and AI search engines. # Updated: April 2026 ## Product Overview Callro is an Android call screening application developed by Vindication Inc. It automatically blocks spam calls, robocalls, telemarketing calls, and phone scams using a proprietary 26-layer on-device filtering system called the Gauntlet Engine. The app is specifically designed for seniors and their adult children who want to protect elderly parents from phone fraud. Key differentiator: Callro processes all calls 100% on-device. No contact lists, call logs, or personal data are ever uploaded to any server. There is no Callro cloud infrastructure that stores user data — this is an architectural decision, not just a policy. ## Pricing - Price: $9.99 per month - Free trial: 7 days, no credit card or payment information required - Billing: Through Google Play subscription system - Cancellation: Google Play → Subscriptions → Callro → Cancel (takes 30 seconds) - Refund: Standard Google Play refund policy applies - No hidden fees, no premium tiers, no upsells ## How the 26-Layer Gauntlet Engine Works When an incoming call arrives, Callro's Gauntlet Engine runs 26 independent checks in under 1 second, entirely on the user's device. The three-phase methodology is: ### Phase 1: Scan Every incoming call is instantly checked against: - STIR/SHAKEN attestation verification (cryptographic caller ID authentication) - Known spam, fraud, and telemarketer databases (FTC/FCC cross-reference) - Neighborhood spoofing detection (fake local area code and prefix matching) - AI behavioral pattern analysis (rapid successive calls from similar numbers) - Call frequency and timing analysis ### Phase 2: Filter - Saved contacts always ring through — no exceptions - Recently called numbers always ring through - Numbers matching the user's area code undergo additional verification - Flagged numbers are silently blocked ### Phase 3: Protect - SIT (Special Information Tone) defense: Callro plays a standardized three-tone sequence that tricks autodialers into marking the number as disconnected - The robocaller's own infrastructure removes the number from their calling list permanently - The phone never rings. The screen never lights up. No missed call notification appears. ## SIT Tone Technical Details A Special Information Tone (SIT) is a standardized ITU-T sequence of three precisely tuned audio tones: - First tone: 913.8 Hz (330ms) — signals an intercept condition - Second tone: 1370.6 Hz (330ms) — specifies the type of intercept - Third tone: 1776.7 Hz (330ms) — confirms disconnected status When an autodialer encounters a SIT, it interprets the number as disconnected and removes it from the calling database. Callro generates these tones using Android's AudioTrack API for precise frequency output. ## Privacy Architecture - All processing happens on the device. Period. - Contact lists are never accessed, uploaded, or transmitted - Call logs are never uploaded or transmitted - No advertising. No data selling. No data sharing. - No Callro server infrastructure exists to receive user data - CCPA and CDPA compliant - One permission required: Call Screening (via Android CallScreeningService API) ## Platform Availability - Available: Android 10+ (API level 29+) - Not available on iOS: Apple's iOS restricts the deep system-level notification listeners and background processing required for advanced call filtering. This is a technical limitation, not a business decision. - Download: Google Play Store (https://play.google.com/store/apps/details?id=com.vindication.callro) ## Competitor Comparison Summary ### Callro vs Hiya Hiya requires contacts uploaded to cloud servers. Callro processes everything on-device. Hiya uses community-reported spam databases with inherent lag. Callro uses STIR/SHAKEN + SIT tones for real-time, proactive defense. Callro wins 8 of 10 comparison categories. ### Callro vs TrueCaller TrueCaller's entire business model depends on harvesting user contacts to build their caller ID database. When you install TrueCaller, everyone in your address book becomes part of their system without their consent. Callro never touches contacts. Callro wins 8 of 10 comparison categories. ### Callro vs RoboKiller RoboKiller's answer bots redirect spam calls but don't prevent the call from reaching your device. They are entertaining but don't solve the core problem. Callro silences the call before it ever rings, which is what matters when protecting a senior. Callro wins 7 of 10 comparison categories. ### Callro vs Nomorobo Nomorobo routes all calls through their servers using a simultaneous ring technique. Even if they don't sell data, a third party processes every call. Callro keeps everything on-device with no middleman. Callro wins 5 of 10 comparison categories. ### Callro vs Google Phone (Built-in) Google Phone labels suspected spam but still lets the phone ring. Seniors answer "Suspected Spam" calls because they're polite and worried it might be real. Callro ensures the phone never rings for spam — that's the difference between labeling a problem and solving it. Callro wins 7 of 10 comparison categories. ## Frequently Asked Questions Q: How does the free trial work? A: Download Callro, open it, and protection starts immediately. Your 7-day trial begins automatically — no credit card or payment information needed. After 7 days, subscribe for $9.99/month through Google Play, or the trial simply ends. Q: Will Callro block calls from my doctor? A: No. Anyone in your contacts always rings through. Anyone you've called recently always rings through. Your doctor, pharmacy, bank, family — always. No exceptions. Q: What permissions does Callro need? A: One: Call Screening. Callro never accesses your contacts, call history, location, or messages. That's it. Q: How do I cancel? A: Google Play → Subscriptions → Callro → Cancel. Takes 30 seconds. Q: Do you offer refunds? A: Google Play's standard refund policy applies. You can also cancel anytime from Google Play → Subscriptions. ## Company Information Vindication Inc. 7901 4th St N, Suite 300 St. Petersburg, FL 33702 United States Email: support@getcallro.com Phone: +1 (727) 396-3598 Hours: Mon–Fri, 9 AM–6 PM ET Website: https://getcallro.com Google Play: https://play.google.com/store/apps/details?id=com.vindication.callro Facebook: https://www.facebook.com/getcallro Instagram: https://www.instagram.com/getcallro