Wiktionary
control characters
n. (control character English)
Usage examples of "control characters".
It is included in the Windows 95 operating system and is the best Windows editing program I have found for handling documents with lots of embedded control characters and other oddities.
From there I download via a dedicated T3 line to an SGI 380SX-VGX at one of AT T's Bell Labs (the one in Boulder, I think - another unofficial account) from where I can further download - and filter out certain offending control characters - to a Mac II at my office.