And you can use some of them as a serial console using a simple TTL to serial voltage adapter.

The following are compatible with 80 columns:

Minitel 1B

Minitel 2

And type the following after power on to switch to 80 cols:

Function T+E

I bought one some time ago, I'm still planning to put a Pi zero W or something similar inside, but never got around to do so.

What you need to build the adapter:

http://pila.fr/wordpress/?p=361

Use online translator and ping me if needed.

Ah, thanks for that article, it might come in handy :)

I thought about doing it this way, but was rather planning to do it slightly differently, by building the right modulator (at, what was it? 2600 bauds? it should be pretty doable to bit-bang using an arduino, or the RPI's GPIO. Maybe even with a digital output, though I'm thinking of using a DAC. Or hell, if using a raspberrypi, why not the audio or video output?

Another option is to bypass the motherboard and use the CRT + keyboard. A friend of mine plans to do just that, and I saw someone post this link on your blog: http://www.cfp-radio.com/realisations/rea48/minitel-01.html

Well, that's for the plans... It's pretty unlikely I'll start this project before 6 months, as I have a lot on my plate :/

Can I use a 230V minitel on a 220V plug in Spain?

We use 50hz too.

Don't see why not, most European equipment is built to handle a range of 220-240V at least, whatever the marking says. At worst the screen might display slightly smaller than intended.

I'm afraid of signal drops.

In 80s, the french electricity network was mostly in 220v. There is no perceptible difference between 220 and 230.

Yes, this will work with 99% proba

I bought one last year and it's honestly pretty fun to get them to work and display a Linux tty. I'll try to get some home automation stuff running on it if I can.