HD Voice over Open SIP
Free World Dialup is back.
Free World Dialup launched in 1995 and became the largest end-to-end IP communication network of its time. Now we're back to help usher in the age of AI communication. Get a number. Talk with people around the world in high fidelity. Experience HD voice the way internet calling was meant to sound.
Hear the difference
Most calls compress your voice. FWD keeps more of the original sound so conversations feel natural. FWD uses wideband audio (AMR-WB) to preserve more of the natural voice range.
Compare HD voice with standard calling and hear the difference for yourself.
AMR-WB wideband — 50 to 7000 Hz · Sample recording
Why wideband audio matters
Traditional telephony limits how much of your voice gets through. Wideband audio captures more detail so conversations sound clearer and more natural.
- ✓Clearer speech
- ✓Less repetition
- ✓More natural tone
- ✓Less listening fatigue
- ✓Better signal for people and software
HD voice quality requires AMR-WB support on both endpoints and a compatible network path. Narrowband fallback applies when conditions require it.
Works with hundreds of compatible devices
From desktop IP phones to mobile apps, a wide range of devices support the audio FWD uses.
What you can do today
- ✓Get your number
- ✓Talk with others on the network
- ✓Experience HD voice
What's coming
- →Conversations that can be saved and used
- →Tools built on top of communication
- →New capabilities for builders
Every call becomes a portable conversation record
Communication is no longer just a call. It becomes something that can be stored, understood, and used.
Cross-channel, not siloed
A conversation can span messages, calls, and follow-ups — all connected in one timeline.
More than a recording
Participants, transcripts, summaries, sentiment, attachments, and metadata — a full system of record.
Privacy and consent built in
Conversations can include consent, security, and controls for how they are used.
AI-ready with provenance
Structured so they can be used by software and AI systems, with traceability for how they are created and used.
Built on open standards
Built on open standards, including work from the IETF.
The record matters as much as the transport
Networks already move voice well. What matters is what you can do with the conversation after it happens.
Builders welcome
If you've ever wanted to build on top of communication itself, this is your starting point. FWD is built with vCons at its core. High fidelity voice creates better input for people, applications, and AI systems.
An experimental network
Free World Dialup is a non-commercial, experimental communication network. It draws inspiration from the principles of Amateur Radio, including those outlined in FCC Part 97.1, which emphasize experimentation, technical advancement, and global communication.