Captcha is a random arrangement of four digits which you must type to run an executable file in Telehack. Its purpose is the confirm that you are human, not a bot. If you fail to type the Captcha, you will be asked to re-enter the code up to five times before you are returned to the previous prompt.
Screenshot of a CaptchaEdit
d8888b. d88888P d8888b. d8888b. `88 d8' `88 `88 .aaadP' d8' aaad8' .aaadP' 88' d8' `88 88' 88. d8' .88 88. Y88888P d8' d88888P Y88888P oooooooooooooooooooooooooooooooo Enter the code: 2732_