LINJEN · AI where nobody expects it.

LINJEN installation

An old Telia booth on a field behind Kivik Art Centre. Lift the receiver and an operator answers; on her side the year is 1962, and she can put you through: England, Moscow, a kitchen in Vitaby. Nothing tells you AI lives here.

LINJEN · the line

00:00tone
00:02it connects
00:03crackle
someone, 1962Hallå? Är det någon där?
00:09your turn.

It stands in the field, and it answers. Gladeholm, Österlen.

the why

Everyone meets AI in a chat window. We hid ours in a telephone.

We set out to build an AI product together. We bought a phone box instead, put it in a field, and made it answer.

a chat windowa telephone

a prompt bar→a receiver

typing dots→someone answers

an onboarding→a printed number board

a disclaimer→nothing at all

Nothing to teach. A whole generation has never even used one, and it still needs no manual.

The point is not the voice. It is being put through.

New voices take over now and then. The first thing people do is hang up and lift the receiver again, to see who they get next.

the test call

I walked out and lifted the receiver.

A rainy test day on the field. Sound on.1:30

A visitor standing inside the booth on a call at night, lit red from the phone

Lit red, from the handset alone.

the catalogue

Not phone numbers. A cast of characters.

····the switchboardsvenska

····Fröken Ura recording

····Englandenglish

····Moscowрусский

····Peking中文

····Americaenglish

····Hamburgdeutsch

····Österbottensuomi

····no catalogue entry?

The numbers are entries in a directory I wrote, printed in the booth and nowhere else. The characters behind them rotate, and new ones are written every week. The line is never the same twice.

Towing the concrete booth home on a trailer with an orange strap, in daylight

Day one: 200 kilos of concrete, two hours from the field.

the work

What the months actually went into.

researchWhich stack survives a field?

Weeks of research before anything was bought: how a call travels, which voice platform can hold a persona, what runs on mobile coverage alone.

firmwareThe phone was never meant for this.

An explosion-rated mine telephone does not speak voice-agent out of the box. I worked with the supplier, sent field reports back, and they sent new firmware. Build after build, until it did.

castingTwelve voices, six languages, one agent.

What does a 1962 switchboard operator sound like in Swedish? How should Moscow answer? Twelve voices, each keeping its own language.

the storyAn open phone. No task, no script.

Every voice-agent demo has one job, book the table, take the order. That is why they feel almost human. This phone has none: anyone can lift it and say anything, and writing a roleplay that survives an open line still isn't done. It is live, and it gets tuned after what actually happens.

receiver→4G router→Twilio→my routing→ElevenLabs voice→Supabase

Solid stands in the field. Dashed lives in the cloud. No computer in the booth.

Working in the booth at dusk with a ladder, the yellow phone visible inside — Install evening. *Change, drive out, lift the receiver, listen.*

the resistance

200 kilos of concrete, online over 4G.

Every check the phone could run came back green. None of it was true.

partit saidthe truth

keypad● OKnever worked from the factory

microphone● OKoff from the factory

the clock● OKreset to 1970 by every power cut

the link● OKsilently dropped big messages

Secured, waterproofed, careful with every watt from the battery. The aim is round the clock through every season, and winter is not solved yet.

built with: industrial SIP phone; 4G + Twilio; ElevenLabs voice AI; Supabase; custom-built TELEFON sign; concept, voice and code: mine; sourcing and installation: with Johan Nygren; self-funded, no grants, no sponsors

The yellow phone and a 4G router on a cardboard box on a workbench, in daylight — A yellow phone. A 4G router. *That's the whole kit.*

under development

Nobody knows which voice you'll get.

Bench numbers from development, not the field: 188 test calls, 91 through the physical receiver, a 64 second median, one that ran ten minutes. The public count starts now.

It runs on a SIM card, a phone bill and a voice API, and it answers for as long as I keep those paid.

what it proves

Everyone demos AI on a screen. I put it in an industrial telephone.

whyclose

A voice AI that answers is the easy part. The months and the long nights went on rain, mobile internet, firmware, and sounding like a person instead of an assistant. It is not a perfect build: self-funded, our own money, and voice tech moves monthly, so the stack under the booth will keep changing. Maybe more booths will start appearing around Sweden.

Somewhere in those nights I worked it out: think like a designer, ship like an engineer.

tl;dr

The whole thing, in five lines.

the pieceA phone booth on a field answers as a 1962 operator and puts you through across the world. No computer in the booth.
the whyEveryone meets AI in a chat window. We hid it inside an interface people learned as children.
the workNo task, no script, anyone on the line. The stack, the firmware with its supplier, twelve voices, a roleplay tuned live.
live nowIt stands in the field and answers. The roleplay gets tuned after what people actually say.
the honest bitSelf-funded, no sponsors. Everything we learned is written down, so booth two is quick work.

the installationThe booth, the field and the yellow phone, on baltsar.art.

You never know who answers.