The other day, someone asked in Sinologic’s Telegram channel whether we were still working with IP telephony or if everything was now artificial intelligence. The question amused me, because it’s one of those questions that, depending on who you ask, can yield very different answers. And the truth is that, even though it might seem odd coming from someone who has lately written quite a bit about TTS, language models, and voice agents, the world of telephony and VoIP is still very much alive despite everything. Perhaps more alive than ever, in fact.
Computing is a field in continuous expansion… what does that mean? Well, today we introduce a way to speak over the internet, and twenty years later we’re talking directly to a bot with a voice so real that no one would doubt it’s a person of flesh and blood. The capacity to advance on technical topics is truly staggering, and sometimes it’s a little dizzying if you stop to think about it.
But yes, we continue with telephony, with VoIP, with programming (despite AI, yes) and with many innovations trying to advance in a niche like computing and telecommunications projects. Although it sometimes seems like nothing moves, perhaps it’s because everyone is moving at the same speed and from the outside it’s hard to distinguish who is advancing and who is simply going with the flow.
AI was supposed to revolutionize everything, and in fact it is doing so, but not in the way many expected. It hasn’t come to replace the telephone; it has come to sit on top of it. To add a layer of intelligence it didn’t have before and to make a phone call go beyond simply being “two people talking” to become something considerably more interesting. And I say “interesting” rather than “unsettling,” though at times the line between the two is thinner than we’d like.
Think about what a PBX was 10 years ago: a system that routed calls, managed queues, played hold music, and little else. Today, that same system can transcribe the conversation in real time, automatically summarize it when you hang up, analyze the customer’s sentiment during the call, and even suggest what to say if it detects things are going sideways. All of this without the end user noticing anything, running silently in the background as if by magic. Of course, a magic that consumes GPU as if there’s no tomorrow and that will have to be paid for someday, but we already discussed that at the time.
But let’s get to the point, since that’s what we’re here for: what is really moving in the world of IP telephony in 2026?
Voice Synthesis and TTS in Telephony: No Longer a Toy
A couple of months ago we talked about the 7 best open source TTS projects that had been popping up like mushrooms, and the landscape has continued evolving at a dizzying pace. Real-time voice synthesis has gone from being “that funny robot-sounding thing” to becoming something that, if you’re not warned, you can’t tell apart from a real person. And in telephony, that’s a brutal paradigm shift.
Right now, any reasonably savvy company can set up an AI-powered phone agent that handles calls 24 hours a day, speaks with a natural voice, understands what it’s asked, and responds with judgment. Is it perfect? Not by a long shot. Is it better than hold music for 20 minutes while someone searches for your file in an Excel spreadsheet? Without a doubt. And here is where telephony has realized that AI is not its enemy, but its best ally, although there is still a long way to go before we can say that a voice agent can replace a human operator with any guarantees.
I still remember when we talked about Vocaloid TTS used to give voice to the world-famous pop star Hatsune Miku back in 2012, and the list of quality TTS systems could be counted on one hand. Today, that anyone can download an open-source model, with an Apache or MIT license, install it on their machine and have an artificial voice indistinguishable from a human one generating audio in real time… well, what can I say, it’s equally impressive and frightening.
The SIP Protocol Remains the Standard for IP Telephony (Even Though Some Declare It Dead Every Year)
Every so often someone appears saying that the SIP protocol is on its last legs, that WebRTC will replace it, that everything will be cloud APIs and that on-premise PBXes will disappear. I’ve been hearing this for more than 15 years and here we are, with SIP going strong as the backbone of virtually all IP telephony in the world. And it doesn’t look like that’s going to change any time soon, honestly.
What has changed is what we do with it. Asterisk, FreeSWITCH and Kamailio are still there, still free software and still evolving. Now you connect an AI engine on one side, a transcription system on another, a vector database on yet another side (yes, ChromaDB and friends) and suddenly, what used to be a PBX that only routed calls becomes an intelligent system capable of understanding what a conversation is about, making real-time decisions and acting accordingly. All of this built on the same SIP protocol as always, the very one some were already burying a decade ago.
And the thing is, WebRTC is great for browsers, for adding a “call” button to a website, or for making a video call without installing anything, but when you need to connect to the traditional telephone network, when you need to do serious things like routing thousands of simultaneous calls, managing SIP trunks with carriers, or setting up a billing system based on CDRs (and I know what I’m talking about, since we’ve been wrestling with 50-million-record tables for years), SIP remains the standard. It’s not sexy, it’s not new, but it works. And in telecommunications, having something that works without giving you scares at 3 in the morning on a Sunday is the most important thing there is.
Cloud PBX vs On-Premise: When Each Option Is Worth It
The business model of IP telephony has changed quite a bit in recent years. The “as a service” model has consumed everything: PBX as a service, trunk as a service, unified communications as a service… everything “as a service” which basically means: you pay every month and if you stop paying, you have nothing. For small businesses with few extensions and no technical staff, it’s probably the most sensible option (let’s be honest: who the heck uses the phone for everything today?). You pay, it works, and move on. But for medium and large businesses, things change significantly.
I’ve seen more than one client (and there have been quite a few) who started paying barely 200 euros a month and three years later was at 1,500 euros because they’d been adding extensions, call recordings, CRM integrations, and a thousand other things that “only cost a little extra per month.” When you run the numbers with a spreadsheet in front of you (the classic strategy used by the window company), in contrast the total cost of Asterisk on your own server works out considerably cheaper from the second year on. That said, it requires someone who knows what they’re doing, and a poorly maintained Asterisk is worse than any cloud PBX, so if you don’t have that resource, stay in the cloud without regrets.
And then there’s the control issue, which few people think about until they need it. We saw it with 3CX’s licensing change: overnight they changed the rules and those who were 100% dependent on their platform got an unpleasant surprise. With free software underneath, at least you can migrate without starting from scratch or asking anyone’s permission. The key is to run the numbers before deciding, not after signing a 24-month contract.
Regulation of Telephone SPAM in Spain: The Rules Are Tightening (And About Time)
Another hot topic in 2026 is the regulation of commercial calls and telephone SPAM. The Ministerial Order TDF/149/2025 that we discussed at the time has started being applied and, although it took a while to arrive, it was necessary. That said, it’s worth separating concepts because they get mixed up too often: one thing is real SPAM—spoofed numbers, calls outside permitted hours, ignoring the Robinson List—and quite another is a company calling you with its paperwork in order to announce something that may interest you. That’s advertising, and it’s been around for centuries; before they knocked on your door, now they call your mobile. Annoying, yes, but legal. You can try to avoid them with mobile apps that intercept calls, but we already explained that you’re giving away your data without knowing it.
The bigger problem is something else, and it’s directly related to what we said about TTS: with models capable of cloning a voice with just 3 seconds of audio (seriously, 3 seconds), it’s no longer just that someone is trying to sell you something, it’s that they can call you in the voice of your bank or your boss asking for something urgent. That is a serious threat and one that isn’t being talked about enough.
Telecommunications operators are required to verify the identity of the caller and to block calls with spoofed numbers, something that should have been done a long, long time ago. However, as always happens with regulation in Spain, between the time a law comes out, gets implemented, and starts being genuinely enforced, months or years pass. Meanwhile, phone number blacklists continue to be a lucrative business for foreign companies that decide who can call and who cannot, without anyone asking them to account for themselves or demanding any transparency. A topic we’ve written about at length and which, unfortunately, remains unresolved.
Why Free Software Remains the Best Bet in IP Telephony
If there’s one thing I’ve learned over all these years (and there have been quite a few), it’s that betting on free software in telephony has never been a bad decision. Asterisk has been around for over 20 years and is still there, more alive than ever with its recent version 23. Kamailio remains the reference for routing millions of calls with the dispatcher module. FreeSWITCH keeps fighting with its flexibility. And all of them have managed to adapt to the new times by incorporating WebRTC support, AI engine integration and compatibility with new standards without anyone needing to pay a license for it. That, when you come from a world where a proprietary PBX license cost as much as a small car, is greatly appreciated.
Even in the world of AI, where it seems like large American companies dominate everything, free software has made its mark with DeepSeek, with models like LLaMA or Mistral, and with tools like Ollama that allow anyone to set up their own AI server without depending on anyone (or sending your data to a server in Virginia). The same has happened with TTS: all the projects we mentioned in January were free, with Apache or MIT licenses, ready for anyone to download, install and put to work.
And this is important, because when France announced it was going to bet on free software to achieve European digital sovereignty, it didn’t do so out of whim or political posturing. It did so because depending on foreign companies’ software for a country’s communications is a vulnerability we cannot afford. And if the April 2025 blackout taught us anything, it’s that telecommunications infrastructure is too critical to leave in the hands of those who can’t even guarantee it works when you need it most. Sovereignty is not bought, it’s compiled… and some European countries have already figured that out.
What Is the Future of IP Telephony and VoIP?
More of the same, but better. IP telephony is not going to disappear, at least not as long as we remain humans who need to speak to one another. What is going to disappear is “dumb” telephony, the kind that only connects two points and lets them talk. The future lies in intelligent communication systems that understand context, that integrate with everything, that are capable of automating tasks and that put artificial intelligence at the service of communication, not the other way around.
Operators are going to have to get serious about security and caller identity verification, whether they like it or not. Integrators are going to have to learn AI one way or another, because clients will ask for things that two years ago were science fiction and can now be set up with a couple of containers and an open-source model. And VoIP PBX manufacturers are going to have to decide whether they keep selling black boxes with ever-more-expensive licenses or bet on more open and flexible models. The 3CX situation was a warning shot: if you change the rules and push too hard, people will find another way. It’s always been like that.
Meanwhile, from Sinologic we will continue doing what we’ve been doing since 2006: talking about IP telephony, VoIP, Asterisk, Kamailio, free software and everything happening in this niche that, despite everything, we still love. People ask if we’re still doing telephony or if everything is AI now… well, both, because VoIP and artificial intelligence are much more connected than they seem. And if you don’t believe it, give it a few months and you’ll see.
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