U+0011 "DC1" DEVICE CONTROL ONE Unicode Character

U+0011 "DC1" DEVICE CONTROL ONE is one of 32 non printing control characters defined in the C0 control code set, originally derived from ASCII standard 1963. It was designed as a transmission control character to turn on or resume a specific peripheral device, such as a printer or tape reader, in a system of multiple devices where each could be individually addressed by its own control code. In modern computing, DC1 is most commonly associated with the XON signal in software flow control, used together with DC3 XOFF to manage data transmission rates and prevent buffer overflow in serial communication, where sending DC1 tells the sender to resume transmitting data.