Your first call

You have a free app for joining, a telnet client, you have picked a board off the list, and it answered. On a BBS that is a first call, a name from the days when you phoned a board to reach it. Here is what happens next.

If you have not installed anything yet, you may not need to. A board that takes SSH answers the ssh command that most computers already have, in Terminal on a Mac and on Linux or in Windows Terminal on Windows: connect with SSH. The rest of this page is then the same, bar one thing, and it saves you a question: an SSH caller is never asked to press DEL or BACKSPACE, because an SSH line is an ANSI terminal either way.

It works out what you are

So its screens look right on whatever you joined from, the board sends a short probe the moment you connect and reads what comes back: ANSI with CP437 or UTF-8, PETSCII at 40 or 80 columns, or plain ASCII. A modern terminal answers the probe and you are asked nothing. If yours stays silent, the board asks you to press DEL or BACKSPACE, which tells it whether you are on a Commodore or a plain ASCII terminal, and a Commodore is then asked whether it has 40 or 80 columns. Each machine gets screens made for it, and they can all sit in the same chat room.

If a board looks like line noise, the probe guessed wrong. Disconnect, set your app's character set to CP437, and connect again.

It asks for a handle

A handle is the nickname other people on the board see. It is not an email address and it is not checked against anything.

Type a handle nobody on that board has taken and it offers you up to three things. The board's host, its sysop, can switch the first two off, so not every board offers all of them:

Register. Pick a password, typed twice, and fill in a short form. It also asks for a name and an email address. Neither is verified, because the board cannot send email: other members can see the name, and only you and the board's staff can see the email. The board then keeps an account for you: your profile, your messages, and however long the sysop allows you per day.
Guest. No account and no password. You keep the handle you typed for that call, you get fifteen minutes on a board with the usual settings, and no account is kept. Lists mark you with a *.
A different handle. Back to the prompt, if that was not the name you meant to type.

Type a handle that already has an account and it asks for the password instead. Three wrong tries and the board hangs up.

Telnet has no encryption. Your password crosses the internet in the clear and so does everything you type. Use a password you use nowhere else, and say what you would say in public. The longer version is here. On an ESP32-S3 board you can call over SSH instead, and then it is encrypted.

Then you are in

Type ? for the menu. Every board is somebody's own arrangement, so the commands differ, but a few are near universal: WHO for who else is on, CHAT for the room, PAGE to get another person's attention, BYE to hang up. A board running this software also has HELP sections, so ? chat shows only the room commands.

There is a person behind it. If something is broken, or you want a feature, the sysop's handle is on the listing and they will almost certainly answer.

What a board knows about you

Your handle, the internet address you connected from, and when and for how long, in a log the sysop keeps so they can see who has been on their own machine. If you registered, what you typed into the sign-up form and your profile: other members can see your name and your profile, and your email, where you are from and your phone number are visible only to you and the board's staff. And whatever you wrote there: mail, forum posts, lines in the chat room. That is the whole list, and the people who run the board can read all of it.