18
DC2
0x12 · 0010010
ASCII 18 — the DC2 character
Not a visible character
DC2 is control code 18, hex 12. You type it as ^R, and it draws nothing on screen.
Characters that draw nothing and instead tell the device to do something.
What this control code did
Device control 2
Device · Codes that rang a bell or switched the character set on a device.
Seven bits
ASCII is seven bits wide, which is why there are 128 of them. The eighth bit was long left for parity.
0010010
One bit — the sixth, worth 32 — separates the cases. Off gives a capital, on gives a lowercase letter.
- Kind
- Control
- Decimal
- 18
- Hexadecimal
- 0x12
- Octal
- 022
- Binary
- 0010010
- HTML entity
- 
- URL encoding
- %12
- CSS escape
- \12
- Ctrl key
- ^R
The chart
Eight columns for the top three bits, sixteen rows for the bottom four. The capitals column sits right beside the lowercase one — that is the shape of the table.
0NUL1SOH2STX3ETX4EOT5ENQ6ACK7BEL8BS9HT10LF11VT12FF13CR14SO15SI16DLE17DC118DC219DC320DC421NAK22SYN23ETB24CAN25EM26SUB27ESC28FS29GS30RS31US32SP33!34"35#36$37%38&39'40(41)42*43+44,45-46.47/48049150251352453554655756857958:59;60<61=62>63?64@65A66B67C68D69E70F71G72H73I74J75K76L77M78N79O80P81Q82R83S84T85U86V87W88X89Y90Z91[92\93]94^95_96`97a98b99c100d101e102f103g104h105i106j107k108l109m110n111o112p113q114r115s116t117u118v119w120x121y122z123{124|125}126~127DEL
Codes either side
How to read this
- Add 32 to a capital and you get the lowercase letter — one bit flips.
- Digits start at 48, so subtracting 48 from the code gives the number.
- Holding Ctrl clears the top three bits — that is why Ctrl+I is a tab.
- Everything under 32, plus 127, draws nothing. Those show their abbreviation instead.
Frequently asked questions
Q. What is the ASCII code for DC2?
Decimal 18, hex 12, octal 022, binary 0010010.
Q. How do I write DC2 in HTML?
As .
Q. How does it go in a URL?
It is encoded as %12.
Q. How do I type DC2?
^R.