If you use Windows 7, you might have opened a Command Prompt and typed telnet hoping to launch the default telnet application. Well, I tried the same and got an error. Turns out that Windows 7 does not have the telnet application installed by default. Most likely this is because Telnet being an old technology, is very insecure and it is recommended that you always use Telnet SSH. If you need to use the default Windows version of Telnet for internal use, you can install Telnet by following these mouse clicks:
Start
Control Panel
Programs And Features
Turn Windows features on or off
Check Telnet Client
Hit OK
After that you can start Telnet via Command Prompt