WiFi Calling

WiFi Calling is an offline voice communication application that allows devices to connect and speak over a shared local Wi-Fi network without requiring internet access or cellular reception.

The application functions as a local peer-to-peer intercom and push-to-talk walkie-talkie. By utilizing direct device-to-device networking on your local area network (LAN), WiFi Calling enables real-time voice conversations across homes, offices, multi-story buildings, and outdoor locations where cellular network coverage is weak or unavailable.

HOW IT WORKS

WiFi Calling operates independently of external servers and telecom carriers. When devices connect to the same Wi-Fi router or personal portable hotspot, the application automatically detects nearby active devices on the subnet using local broadcast signals.

Once a peer device appears on your radar screen, you can initiate a standard two-way call or use push-to-talk walkie-talkie mode. Audio is transmitted directly between the two devices across your local network with low latency and hardware-accelerated echo cancellation.

COMMUNICATION MODES

1. Full-Duplex Wi-Fi Calling
Make continuous, two-way voice calls similar to a conventional phone call. Both parties can speak and listen simultaneously. You can toggle between earpiece and speakerphone, mute your microphone, and monitor real-time network latency in milliseconds.

2. Push-to-Talk (PTT) Walkie-Talkie
Communicate in half-duplex walkie-talkie mode. Press and hold the button to transmit your voice, and release it to listen. The microphone remains muted until pressed, reducing background noise and saving network bandwidth.

KEY FEATURES

- Automatic Peer Discovery: Interactive radar display continuously scans your local Wi-Fi network to detect active devices.
- Subnet Scanner: Built-in local subnet sweeper locates devices on networks with strict broadcast filtering.
- Direct IP Connection: Connect directly to another device by entering its local IP address, bypassing router restrictions.
- Network Diagnostics: Integrated testing utility checks your local interface, subnet broadcast address, and AP isolation settings.
- Audio Quality: Voice processing includes acoustic echo cancellation, noise suppression, and automatic gain control.
- Low Latency: Audio travels directly across your local network rather than through cloud servers, keeping voice delay minimal.
- Identity Customization: Set your display name and avatar color so others on the network recognize your device.

TYPICAL USE CASES

- Home Intercom: Talk between rooms or floors in a house without shouting or cellular minutes.
- Poor Cellular Reception: Stay in contact inside basements or concrete structures where phone signals cannot reach but local Wi-Fi is available.
- Off-Grid Trips: Create a Wi-Fi hotspot on one phone and connect other devices for offline voice calls while camping or hiking.
- Office and Workplace: Coordinate team members in offices, warehouses, and shops without internet connectivity.
- Devices Without SIM: Turn old phones or tablets into functional intercom units for family members.

PRIVACY AND PERMISSIONS

WiFi Calling requires no accounts, phone numbers, or passwords. Voice audio is never recorded, stored, or sent to cloud servers.

- Microphone: Required to transmit your voice during calls and walkie-talkie sessions.
- Nearby Wi-Fi Devices: Required on modern Android versions to discover peer devices on the local network.

REQUIREMENTS

Both devices must connect to the same local Wi-Fi network or a shared mobile hotspot. An internet connection or mobile data plan is not required.