Kontrollzeichen

Kontrollzeichen are non-printing characters used in data transmission and text processing. They serve specific functions rather than representing visual symbols. These characters are typically part of character encoding standards like ASCII and Unicode.

Common control characters include those for carriage return (CR), line feed (LF), backspace (BS), and tab (TAB). For example, CR and LF are often used in combination to signify the end of a line in text files. The backspace character moves the cursor one position back, and the tab character advances the cursor to the next predetermined stop.

Other control characters have roles in communication protocols, such as Start of Text (STX) and End of Text (ETX), which delineate the boundaries of a message. Flow control characters like XON and XOFF are used to manage the rate of data transmission between devices.

Historically, control characters were crucial for operating teletype machines and early computer terminals. While many have been superseded by more sophisticated mechanisms in modern operating systems and network protocols, some remain fundamental to text file formats and basic character encoding. In programming, control characters are often represented using escape sequences, such as \n for newline or \t for tab. Their presence can sometimes lead to unexpected behavior if not handled correctly, especially when transferring data between different systems with varying interpretations of these characters.