Definition:Baudot Code

Definition

The Baudot code is a binary code for telegraphy.

Each character in the alphabet is represented by a series of five bits, sent over a transmission line.

Baudot code (European and UK versions)

Code					Europe		UK
$\text {V}$	$\text {IV}$	$\text {I}$	$\text {II}$	$\text {III}$	Letter	Digit	Letter	Digit
					blank	blank	blank	blank
		$\bullet$			$\text A$	$1$	$\text A$	$1$
			$\bullet$		$\text E$	$2$	$\text E$	$2$
		$\bullet$	$\bullet$		$\acute {\text E}$	$/$	$\&$	${}^1 /$
				$\bullet$	$\text Y$	$3$	$\text Y$	$3$
		$\bullet$		$\bullet$	$\text U$	$4$	$\text U$	$4$
			$\bullet$	$\bullet$	$\text I$	$\underline {\text o}$	$\text I$	${}^3 /$
		$\bullet$	$\bullet$	$\bullet$	$\text O$	$5$	$\text O$	$5$
	$\bullet$				Digit $\dagger$	blank	Digit $\dagger$	blank
	$\bullet$	$\bullet$			$\text J$	$6$	$\text J$	$6$
	$\bullet$		$\bullet$		$\text G$	$7$	$\text G$	$7$
	$\bullet$	$\bullet$	$\bullet$		$\text H$	$\underline {\text h}$	$\text H$	${}^1$
	$\bullet$			$\bullet$	$\text B$	$8$	$\text B$	$8$
	$\bullet$	$\bullet$		$\bullet$	$\text C$	$9$	$\text C$	$9$
	$\bullet$		$\bullet$	$\bullet$	$\text F$	$\underline {\text f}$	$\text F$	${}^5 /$
	$\bullet$	$\bullet$	$\bullet$	$\bullet$	$\text D$	$0$	$\text D$	$0$
$\bullet$					blank	Letter $\ddagger$	blank	Letter $\ddagger$
$\bullet$		$\bullet$			$\underline {\text t}$	$.$	$-$	$.$
$\bullet$			$\bullet$		$\text X$	$,$	$\text X$	${}^9 /$
$\bullet$		$\bullet$	$\bullet$		$\text Z$	$:$	$\text Z$	$:$
$\bullet$				$\bullet$	$\text S$	$;$	$\text S$	${}^7 /$
$\bullet$		$\bullet$		$\bullet$	$\text T$	$!$	$\text T$	${}^2$
$\bullet$			$\bullet$	$\bullet$	$\text W$	$?$	$\text W$	$?$
$\bullet$		$\bullet$	$\bullet$	$\bullet$	$\text V$	$'$	$\text V$	${}^1$
$\bullet$	$\bullet$				Erasure	Erasure	$*$	$*$
$\bullet$	$\bullet$	$\bullet$			$\text K$	$($	$\text K$	$($
$\bullet$	$\bullet$		$\bullet$		$\text M$	$)$	$\text M$	$)$
$\bullet$	$\bullet$	$\bullet$	$\bullet$		$\text L$	$=$	$\text L$	$=$
$\bullet$	$\bullet$			$\bullet$	$\text R$	$-$	$\text R$	$-$
$\bullet$	$\bullet$	$\bullet$		$\bullet$	$\text Q$	$/$	$\text Q$	$/$
$\bullet$	$\bullet$		$\bullet$	$\bullet$	$\text N$	$\text N^{\text o}$	$\text N$	$\pounds$
$\bullet$	$\bullet$	$\bullet$	$\bullet$	$\bullet$	$\text P$	$\%$	$\text P$	$+$

The columns are arranged in the order they are, that is:

$\text {V}$, $\text {IV}$, $\text {I}$, $\text {II}$, $\text {III}$

because that is how they were arranged on the original machines that were used to perform the encoding.

$\dagger \quad$ After receiving this code, all following codes are interpreted as digits until the next Letter code.

$\ddagger \quad$ After receiving this code, all following codes are interpreted as letters until the next Digit code.

Source of Name

This entry was named for Émile Baudot.

Historical Note

The Baudot code was invented by Émile Baudot in the $1870$s.

It was widely used in telegraphy.

It superseded Morse code but has now been mostly replaced by ASCII.

Sources

• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): Baudot code