How Linphone Integrates “Real-Time Text” Support in Baudot Mode to Extend the Life of Existing Technologies

With the gradual disappearance of copper lines, many infrastructures are forced to upgrade their existing technologies. As a result, often expensive equipment risks becoming obsolete even though it is still functional. To avoid this technological waste, we have chosen a more responsible approach: adapting our modern solution to these existing systems to extend their lifespan and reduce planned obsolescence.

Reverse Engineering in Service of Digital Transition

The Baudot protocol, developed in the 1970s, was long used in TTY/TDD terminals to enable hearing-impaired people to communicate via text over analog telephone lines. Although it is no longer compatible with most modern technologies, it is still in use today, notably in North America and Europe.

As part of a client project, we integrated a compatibility layer for this protocol into Liblinphone. The result: our solution can now operate as a SIP client compatible with TTY, capable of exchanging real-time text over VoIP.

Use Case for a Smooth Migration

The client, transitioning to modern RTT (Real-Time Text) solutions, needed to maintain compatibility with still-used TTY terminals. Integrating Baudot mode into Liblinphone ensured this continuity without service interruption. This coexistence between modern telephony software and legacy protocols enabled a gradual transition, avoiding waste of still-functional equipment — an economically and ecologically sound choice.

This project reflects our commitment to responsible and sustainable technology. Whereas some solutions force updates that break compatibility with existing systems, we chose to build a bridge between technological generations.

By extending the life of older equipment through modern software, we offer a concrete alternative to planned obsolescence that benefits both users and the planet.