ASCII 2 — STX

Start of Text (STX) indicates the beginning of the actual message body following the header initiated by SOH. Together, SOH and STX created a simple framing protocol: header data appeared between SOH and STX, while the payload followed STX. Modern serial protocols and barcode scanners still rely on STX/ETX framing for reliable message delimitation. In terminal applications, Ctrl+B generates the STX character and is typically remapped to editing functions like toggling bold text formatting.

Control characters were defined in the original 1963 ASCII standard to manage telecommunications equipment and terminal devices. Unlike printable characters representing visible symbols, control codes perform actions: initiating transmissions, acknowledging received data, triggering device alerts, and structuring information hierarchically. Of ASCII's 128 code points, 33 are designated as control characters (codes 0–31 plus 127), reflecting the standard's deep roots in telegraphy and serial communication systems. While most control codes have fallen out of daily use, several remain essential to modern computing workflows.

In the ASCII encoding table, Start of Text is assigned code point 2 in decimal (0x02 hexadecimal, 002 octal, 00000010 binary). The 7-bit ASCII standard, first published in 1963 by the American Standards Association, defines exactly 128 characters that remain the foundation of text encoding systems worldwide. UTF-8, the dominant encoding on the modern web, is fully backward compatible with ASCII — every ASCII character is encoded as the identical single byte in UTF-8, guaranteeing that Start of Text works reliably across all operating systems, programming languages, and internet protocols.