Are there free online learning systems available?

Question

Distance learning

Good afternoon,
there is a task to organize online training, the goals are primitive:
1. See the speaker.
2. Hear the speaker.
3. The ability of the speaker to switch the video to his PC (for example, to show some software in operation)
The goal is this: deploy your server with a certain server solution, the speaker connects and the listeners connect. Do not offer third party services.
Is there something free in this direction, or at least not for a Million US dollars.
If there is, please advise.

Answer 1

look in the direction of TrueConf, though you will need to install clients for users...