U+0001 "SOH" START OF HEADING Unicode Character

U+0001 "SOH" START OF HEADING is a control character originally defined in ASCII and later adopted into Unicode, designed to precede and indicate the start of a header block in a data transmission stream. Historically used in telecommunications and early computer protocols, SOH helps structure data by signaling to a receiver that the following bytes contain metadata, such as addressing or routing information, before the main message body begins. Although not visible in typical text output, it remains a fundamental part of legacy serial communication standards and specific modern data formats requiring discrete control sequences.

General Properties

Code Point	U+0001
Version Added	1.1
Unicode 1.0 Name	Start of Heading
Block	Basic Latin
General Category	Control
Canonical Combining Class	Not Reordered
Bidirectional Class	Boundary Neutral
Alias	SOH (abbreviation) START OF HEADING (control)

Encodings

HTML Decimal Encoding	
HTML Hex Encoding	
UTF-8 Encoding	0x01
UTF-16 Encoding	0x0001
UTF-32 Encoding	0x00000001
C/C++/Java Escape	\u0001

Unicode Properties

NFC Quick Check	Yes
NFD Quick Check	Yes
NFKC Quick Check	Yes
NFKD Quick Check	Yes
Numeric Type	None
Numeric Value	NaN
Line Break	Combining Mark
Script	Common
Script Extensions	Common
Indic Syllabic Category	Other
Vertical Orientation	Rotated
Grapheme Cluster Break	Control
Word Break	Other
Sentence Break	Other