Still can't find information about what hardware can be connected???

In your account you just can see the pools you can connect to Minerboard as well as the coins

Does it mean that I can't see information about the specific kind of mining hardware I can connect to minerboard

Yes. We didn't add this information on our website.

How then should I understand whether I can connect my equipment to minerboard?

You will have enough information about the supported pools and algorithms to connect to minerboard.