Beginner's Guide to Minitel
by NeurAlien
From CORE-DUMP, a French hacker publication.
The Minitel is only the terminal of the TELETEL network. We often say Minitel when we should say TELETEL. The Minitel was at the beginning only a Videotex terminal. It could display only 40 columns and could do only videotex (there was no RETOUR key for example). That was the shitty MINITEL 1 (the first MINITEL 1 had an ABCD keyboard instead of an AZERTY keyboard as on every French computer, to show you how shitty it was).
Now there are a lot of Minitels:
MINITEL 1B: It can be set to four modes: Videotex, American TTY, French TTY, French TTY with Minitel's key.
MINITEL 2: It's nearly the same as M1B but it can display more precise graphics (Dynamically Redefinable Character Set [DRCS] graphics), can dial by itself, can communicate at 9600 bps with the computer (instead of 4800 for the M1B), can detect the ring and can be protected by password (which can be bypassed... hehe!!!)
MINITEL 5: Tiny Minitel for travel with LCD display and other features.
MINITEL 10: Old... The phone is integrated into the Minitel.
MINITEL 12: The phone is integrated into the Minitel and you can make a Minitel responder (like a little Videotex server). You can also protect this one with a password. The display is made in 40 columns for the Videotex mode. It can display characters or low-resolution graphics for the non-DRCS Minitels.
The Minitel protocol is called V.23, data is sent to TELETEL at 75 bps (that sucks!) and Minitel receives data at 1200 bps. The settings are: 1200,E71 (1200 bps, Even Parity, 7 Data Bits, and 1 Stop Bit).
The MINITEL Keys
SOMMAIRE (INDEX): Go to upper menu.
REPETTITION (REPEAT): Display once again the screen.
SUITE (NEXT): Display the next screen/message.
RETOUR (BACK): Display the previous screen/message.
GUIDE (HELP): Display a HELP screen.
CORRECTION (CORRECT): Erase the previous character typed.
ANNULATION (ERASE): Erase the whole line of text typed.
CONNEXION/FIN (CONNECT): Tell the modem to be ready to answer to the carrier.
FNCT (FUNCTION): Key used to change the Minitel into another mode from the current. (Avoid the device plug connected to the computer or the device which restricts the access to T1 for example hehe...)
ENVOI (SEND): Equivalent to RETOUR but in Videotex mode.
All of the functions described are up to the server which can interpret in the way it needs/wants the escape codes sent Videotex codes.
These are a set of escape codes which can be interpreted by the Minitel or the Minitel emulation program.
There are a lot of different kinds of characters: position codes, movement codes, repetition codes, character size codes, attribute codes, color codes, etc.
The TELETEL Networks
TELETEL is in fact only an add-on to some PAD to make TRANSPAC (the French X.25 network) compatible with the V.23 protocol.
The PADs for the Minitel are called PAVI (Point d'Accès Vidèotexte). These PAVI offer different services:
- 3613 - TELETEL 1 (T1)
- 3614 - TELETEL 2 (T2)
- 3615 - TELETEL 3 (T3)
The prices increase with the TELETEL number.
3605XXXX is a number for free but restricted Videotex server (TELETEL 0). When you dial a T0 number, you usually log onto a closed server which provides access only for authorized users. The 3613 is the number to dial on the phone to access from everywhere in France to the T1.
You dial it, then, when you hear the carrier, you hit CONNEXION/FIN. It logs you onto the TELETEL 1.
Then a screen appears and invites you to type either an NAB or a local TRANSPAC number in this format:
Where SA is a sub-address used by the server which can be up to 5-digit, it's usually not used.
A NAB is a short name to which is given a TRANSPAC number in the PAVI's routing tables.
Then you hit ENVOI and it connects you to the Videotex server.
Inside TELETEL
In fact, when you log onto a PAVI, you log onto a Videotex PAD which can understand the Minitel's keys and can display Videotex screens. That's all. On those PAVIs, you can use X.3 commands (or X.28).
When you type the NAB, it connects you to the TRANSPAC address it has found in its routing tables which is set: EQUAL TO <NAB>
The PAVI then is like any PAD.
Now the server can detect if the user is connected via T1, T2, or T3 (or others).
When the PAVI make an X.25 call, the X.25 address of the PAVI is given to the server.
This address has this format:
The last digit tells the server from which TELETEL (3613, 3614, 3615, etc.) the user calls and thus, the server can provide a full, restricted, or closed access.
When a user calls from 3615, it gives money to the server. From 3614, nothing to the server. From 3613, it costs some money to the server.
The NTI Facility
This allows a Minitel user to make international calls.
With an Network User Identification (NUI) and a Network User Address (NUA), you can do this: call 3613, type as the service name your NUA preceded by 0
Example: 03132000000
Hit SUITE, type your NUI, hit ENVOI.
Then it connects you to the NUA which has been given. The call is made via the NTI which checks the validity of the NUI and make the gateway between TRANSPAC on the other X.25 network.
The NUI consists of six alphanumeric characters.
Conclusion
So, as you can see, this is a short introduction and if we decided to explain everything in the Minitel or in the TELETEL network, we couldn't do it in one month even if we were working 25-hours-a-day. But we have some document about the escape codes, the network architecture, and so on which we will share if there's an interest.
So, if you need something about that, contact me on 3614 code LEGEND (LEGEND is for example a NAB) and my BAL (mailbox) is NeurAlien.
We are going to make a Videotex and international X.25 server and then it will be easier to contact us.