Technically, telnet is a protocol. This means it is a language that computer use to communicate with one another in a particular way.
From your point of view, Telnet is a program that lets you login to a site on the Internet through your connection to Access. It is a terminal emulation program, meaning that when you connect to the remote site, your computer functions as a terminal for that computer.

Once the connection is made, you can use your computer to access information, run programs, edit files, and otherwise use whatever resources are available on the other computer. What is available depends on the computer you connect to.

Note: telnet connections give you command-line access only. In other words, instead of being able to use buttons and menus as you do with a graphical interface, you have to type commands. However, telnet allows you to use certain utilities and resources you cannot access with your other Internet applications.