DC1
Device Control One (XON)
ControlASCII 17 | Hex 0x11 | U+0011
DC1 (code 17), commonly called XON, resumes data transmission in software flow control. The XON/XOFF protocol pairs DC1 (resume) with DC3 (pause) to prevent buffer overflows on serial connections. Terminal emulators still support this: pressing Ctrl+S sends XOFF and freezes terminal output, while Ctrl+Q sends XON to resume it. This catches many developers off guard when they accidentally press Ctrl+S and their terminal appears to hang.
ASCII Code
Decimal
17
Hexadecimal
0x11
Octal
21
Binary
0001 0001
Unicode
Code Point
U+0011
Escape
\u0011
UTF-8 Hex
0xE2 0x90 0x91
UTF-8 Binary
111000101001000010010001
UTF-16
0x0011
UTF-32
0x00000011
HTML Entities
Numeric

Hex

How to Type
HTML Entity

Unicode InputU+0011
Source Code Representations
C / Java
"\u0011"CSS
\0011JavaScript
"\u0011"Perl
\x{0011}Python 2
u"\u0011"Python 3
\u0011Ruby
\u{0011}Frequently Asked Questions
What is ASCII code 17?
ASCII code 17 represents the Device Control One (XON) character. In hexadecimal it is 0x11, in binary 0001 0001, and in octal 21. This is a non-printable control character used for device signaling and data transmission control.
How do I type ASCII 17 on a keyboard?
Control characters are typically entered using Ctrl key combinations. For example, Ctrl+Q produces ASCII 17 in most terminal emulators. You can also use the HTML entity  in web pages.