What Uniline is

Uniline is a compact device that connects to a standard analog phone line and lets a phone or laptop use that line as a multi-mode communication channel. It is designed for situations where modern networks are degraded, unreliable, or unavailable.

Instead of assuming working cellular data or internet access, Uniline assumes only that a copper line still has dial tone or can reach another line through the PSTN. On top of that minimal assumption, it provides three integrated capabilities: encrypted data, TTY text, and voice/buttset functionality.

Core capabilities

Uniline is built around a single line interface that can be used in different ways depending on the environment and the user’s needs:

• encrypted low-bandwidth data — establishes a modem link between two endpoints and runs an encrypted message/telemetry channel on top, suitable for text, status updates, coordinates, and small sensor packets.
• TTY text calls — sends and receives Baudot TTY tones so text calls can work on degraded lines or with relay services, and so accessibility-oriented call paths stay usable even when other infrastructure is unreliable.
• voice and buttset mode — allows a phone to act as a handset via USB-C or Bluetooth, so the device can function as a field telephone or lineman’s buttset for diagnostics and emergency calls.
• high-impedance monitoring — listens to a line without seizing it, useful for checking dial tone, line noise, alarm dialers, or existing modem/TTY activity.

These capabilities share the same physical line and are coordinated through simple modes: a data mode for digital messages, a monitor mode for passive listening, and a talk mode for voice/TTY calls.

How it works

Uniline lives between a phone or laptop and an analog phone line:

• the phone or laptop connects over USB-C or Bluetooth and acts as the user interface for text, status, and audio.
• the Uniline node provides an FXO-style line interface, handling isolation, off-hook control, and analog audio.
• a small modem and TTY DSP layer manages data modulation, TTY tone handling, and line-level signaling.
• an optional encryption layer secures the digital data channel between two nodes.

From the user’s point of view, this looks like a very small, purpose-built “line adapter” that can be told to either send encrypted messages, behave as a TTY/text terminal, or act as a basic phone handset.

Use in crisis and collapse scenarios

In conflict zones, civil unrest, or infrastructure collapse, cellular and internet networks are often the first to degrade or disappear. Analog lines sometimes remain reachable for longer because they are centrally powered, simpler, and historically designed for survivability.

Uniline is intended to help in those scenarios by offering:

• basic encrypted messaging between clinics, shelters, and local hubs when IP networks are down.
• simple, low-bandwidth coordination channels for medical aid, supply routing, and check-ins between communities.
• fallback paths for family contact and “I’m safe” updates when other communication channels fail.
• TTY-based communication on highly degraded lines or with legacy relay services, preserving an older but robust text-call path.
• backup voice and buttset functionality when no other phones are available, while still using a familiar smartphone interface.

The goal is not to replace modern networks, but to keep a minimal, human-centered channel open when those networks are unstable.

Design principles

Work on Uniline is guided by a few principles:

• resilience — prefer simple, low-power designs that work in degraded conditions.
• universality — support data, voice, and TTY over a single analog interface where possible.
• neutrality — avoid ideological framing; focus on practical continuity of communication.
• accessibility — treat TTY and text calling as first-class, not legacy afterthoughts.
• openness — keep designs, reasoning, and tradeoffs visible and remixable.

Uniline does not claim to be a finished or certified system. It is an evolving exploration of what can be done with the modest but still powerful capabilities of analog phone lines.

Scope and ethics

The focus is on civil resilience: helping people coordinate, stay in contact, and share essential information under stress, not on exploitation of infrastructure.

Status

Uniline is currently in a design and exploration phase. Hardware, firmware, and cryptographic components are experimental and not suitable for critical life-safety use without further review, testing, and independent validation.

The repository is available at: github.com/dev11systems/uniline.

License

All Uniline documentation and reference designs are released under a CC0 / public domain dedication. Use, modify, or extend freely, including for commercial and derivative work.