Direct connect is a peer-to-peer file-sharing protocol. Direct connect clients connect to a central hub and can download files directly from one user to another.
Hubs feature a list of clients or users connected to them. Users can search for files and download them from other clients, as well as chat with other users.
The Direct connect protocol is a text-based protocol, where commands and their information is sent in clear text, without encryption. As clients connect to a central source of distribution (the hub) of information, the hub is required to have a substantial amount of upload bandwidth available.