If you use Linux, you must first install the telnet package with the following commands:

Deb based distros, Ubuntu, Debian, Mint, Kali:

$ sudo apt install telnet

Rpm based distros, Fedora, CentOS, RHEL

$ sudo yum install telnet

Now that the telnet package is installed, simply input the following into your terminal:

$ telnet IP Port

An example,

$ telnet 127.0.0.1 26910

You will now be connected to your telnet session. Simply provide your password, and you will have successfully logged in to your 7 Days to Die Telnet-based remote console.