ASCII 22
ASCII 22 is Synchronous Idle — the control character SYN.
Every representation
| Character | SYN (not printable) |
| Name | Synchronous Idle |
| Decimal | 22 |
| Hexadecimal | 0x16 |
| Octal | 0026 |
| Binary | 00010110 |
| HTML entity |  |
| Escape sequence | \x16 |
| Unicode | U+0016 |
| Keyboard | Ctrl+V |
| Group | Control character |
What it is for
Sent to keep a synchronous link in step when there was no data to send. The name survives in the TCP SYN packet.
Where the number comes from
Codes 0 to 31 were reserved for control: instructions to a teleprinter rather than characters to print. Code 22 is Ctrl+V because the Ctrl key was originally wired to clear the top two bits of whatever you typed, mapping the letter V at 86 down to 22.
Frequently asked questions
What is ASCII 22?
Synchronous Idle (SYN), a control character. In hexadecimal it is 0x16, in octal 0026, and in binary 00010110.
How do I type ASCII 22?
Press Ctrl+V in a terminal. In a string literal you can write it as \\x16 in most languages.
Is ASCII 22 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 15 — SI
- ASCII 16 — DLE
- ASCII 17 — DC1
- ASCII 18 — DC2
- ASCII 19 — DC3
- ASCII 20 — DC4
- ASCII 21 — NAK
- ASCII 23 — ETB
- ASCII 24 — CAN
- ASCII 25 — EM
- ASCII 26 — SUB
- ASCII 27 — ESC
- ASCII 28 — FS
- ASCII 29 — GS
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