ASCII 5
ASCII 5 is Enquiry — the control character ENQ.
Every representation
| Character | ENQ (not printable) |
| Name | Enquiry |
| Decimal | 5 |
| Hexadecimal | 0x05 |
| Octal | 0005 |
| Binary | 00000101 |
| HTML entity |  |
| Escape sequence | \x05 |
| Unicode | U+0005 |
| Keyboard | Ctrl+E |
| Group | Control character |
What it is for
Asked the receiving station to identify itself. Obsolete outside legacy serial links.
Where the number comes from
Codes 0 to 31 were reserved for control: instructions to a teleprinter rather than characters to print. Code 5 is Ctrl+E because the Ctrl key was originally wired to clear the top two bits of whatever you typed, mapping the letter E at 69 down to 5.
Frequently asked questions
What is ASCII 5?
Enquiry (ENQ), a control character. In hexadecimal it is 0x05, in octal 0005, and in binary 00000101.
How do I type ASCII 5?
Press Ctrl+E in a terminal. In a string literal you can write it as \\x05 in most languages.
Is ASCII 5 printable?
No. Codes 0 to 31 and 127 are control characters — they were instructions to a teleprinter rather than marks on paper, and most terminals show nothing for them.
Nearby codes
- ASCII 0 — NUL
- ASCII 1 — SOH
- ASCII 2 — STX
- ASCII 3 — ETX
- ASCII 4 — EOT
- ASCII 6 — ACK
- ASCII 7 — BEL
- ASCII 8 — BS
- ASCII 9 — HT
- ASCII 10 — LF
- ASCII 11 — VT
- ASCII 12 — FF
Full ASCII table · Text to binary converter · Number base converter