Encrypted control of remote computers using the RDP protocol is accomplished using what port number?

TCP 3389.

Explanation:

Encoded remote access control using the Remote desktop protocol is performed using the following port number.

Windows RDP deploys TCP Port 3389 but also is mostly used by Windows Terminal Server. Within Firewall, every user will still need to enable or allow such port to grant other device control of the user's computer, whether on the specific network or from another network.