Hello Everyone, i joined the forum because i have a goal: Learn the minitel/videotel standard and create a server that everyone with a terminal can dial and have some fun with it ! Now thanks to the awesome work of Jelora from what i undestood connecting somethig like a raspberry pi should be almost straightforward. I would like to create a PCB that everyone on the forum can get and have made from companies like PCB Way and JLCPCB but in the first place i have to understand how minitel works and establish a base point to begin. I found this schematic on jelora website as a sort of development board did you guys think could be a good idea build such a board to begin ?
You can use directly the modem V.23 of your videotel terminal. For my server, i do not maked a modem on a PCB, I used the returned modem of a minitel 2.
This schematic allow you to connect your Minitel with the phone plug to a simulated phone line.
But if you just want to test the Videotext standard to displays things on your screen, you can use a simple serial to DIN (the connector on the back of the Minitel) adapter.
This machine can be use as a simple serial terminal.
You have this schematic to do that but it doesn’t the RS232 specifications :
You have this one to connect your Minitel to a RS232 interface compliant to RS232 specifications :
And you have this one with a USB interface :
I created my developpement modem to connect my Minitel like a normal one on a phone line and keep the DIN connector for something else.
Let’s split you goal into sub ones…
- play with your terminal and the videotex standard
- run a server to allow other terminals to connect to it
It is best to start with the first part… because it is necessary for the second
You’ll need to connect your terminal to a computer (this includes also things like Raspberry Pi or Arduino microcontrolers).
If I remember correctly, the SIP videotel terminal has a DB25 connector, no DIN5 like the french Minitel.
I imagine it is a plain RS232 serial interface, so you need some RS232 serial interface on the other (somputer) side.
Maybe you should post some photos of your SIP videotel terminal to be sure about that…
For the videotex part, I wrote a small python module that simplifies writing videotex servers. You can use it with a terminal locally connected thru a serial port, and you can also use it to create a websocket based server on which a videotex terminal (made by @zigazou) can connect from a web browser. It can also be adapted to run a real server on a phone line.
Ok guys, thank you very much for all the informations anf for all the answers, right now i have only one terminal, the alcatel ADF-258 that on the back have a din connector, the fun story is that i already have rs232 to din and usb to din converters because i used this terminal as a serial terminal so i only need to find them again (never realized that trought that port i could also do videotel) anyways i’m waiting 2 more terminal a philips one (that as cquest said have a db25 on the back) and another one but it is a surprise so you have to wait a little bit for that. Now in the following days i will find/rebuild a cable to connect a raspberry pi to minitel and start to play with it. I’m very happy to see you guys so interested with my project , thanks a lot to all of you, I’m very happy to be here
Share pictures of all of them, for the museum
Sure, there will be a lot of Pictures a couple of questions for jelora:
Did you think i can use CH340C instead of the PL2303 ? (CH340C have onboard xtal so no external is needed)
In the schematic i posted of your development modem i see 2 integrated circuit : 4116N and 4069N is it possible to have a more complete part number ? I’m unable to find them on the market (ebay, RS-Online, Mouser)
Thank You so much for your time
I don’t know for Itilian Minitels but it’s not possible to use a CH340 with a French Minitel because Minitels use 7 bit words and the CH340 can only create 8 bits words. This is why I used PL2303 instead of CH340.
4016 (not 4116 ) and 4069 are common ICs from the CD4000 series. Try to seach CD4016 et CD4069.
Yes, I read it Wrong, it was the CD4016 Sorry for that, Just a little Update, today i re-made the serial cable and it appears to be working, below a coupe of pics:
Now, how can i play with Minitel a little bit ? You guys mentioned a python script to show something on the screen if i remember correctly…
Have a look at https://github.com/cquest/pynitel
It worked like a charm, in 80 column mode this little crt is awesome to read, a very nice piece of hardware ! I’m almost sure the protocol used here in Italy was exactly the same !!
a picture for you guys:
Thank You so much for the help ! I’m confident We’ll made my future server working !!
Hello Guys, a quick UPDATE, i’m now wiring my protoboard to study a bit the minitel working principle and here is some pictures,
And a Leffe Rouge for the good Jelora because he helped me a LOT, Thank You Very Very Much !
Oh thank you for the beer !