ENQ
Enquiry
ControlASCII 5 | Hex 0x05 | U+0005
ENQ (code 5) requests a response from a remote station. In BSC protocol, sending ENQ asks "are you ready to receive?" In the Hayes modem AT command set, the sequence +++ATH used ENQ-like polling to check modem status. Some point-of-sale payment terminals still use ENQ/ACK handshaking to establish communication before transmitting transaction data. Outside legacy serial protocols, ENQ has no modern equivalent because TCP handles connection establishment at a lower layer.
ASCII Code
Decimal
5
Hexadecimal
0x05
Octal
5
Binary
0000 0101
Unicode
Code Point
U+0005
Escape
\u0005
UTF-8 Hex
0xE2 0x90 0x85
UTF-8 Binary
111000101001000010000101
UTF-16
0x0005
UTF-32
0x00000005
HTML Entities
Numeric

Hex

How to Type
HTML Entity

Unicode InputU+0005
Source Code Representations
C / Java
"\u0005"CSS
\0005JavaScript
"\u0005"Perl
\x{0005}Python 2
u"\u0005"Python 3
\u0005Ruby
\u{0005}Frequently Asked Questions
What is ASCII code 5?
ASCII code 5 represents the Enquiry character. In hexadecimal it is 0x05, in binary 0000 0101, and in octal 5. This is a non-printable control character used for device signaling and data transmission control.
How do I type ASCII 5 on a keyboard?
Control characters are typically entered using Ctrl key combinations. For example, Ctrl+E produces ASCII 5 in most terminal emulators. You can also use the HTML entity  in web pages.