Crate letratag_protocol 

Offline LetraTag LT-200B wire encoding. Not verified against real hardware.

Structs

Job

Raster

A full 32-row frame, in row-major order, containing only 0 (white) or 1 (black).

Enums

Error

Profile

Status

Constants

CASSETTE_ID_12MM

Cassette id 3: 12 mm tape (the only width the LT-200B chassis accepts). The id enum is shared by the ESC M directive and the advertising-data cassette field (S2 docs/protocol/letratag-bt.md): 1=6mm, 2=9mm, 3=12mm, 4=19mm, 5=24mm.

HEAD_ROWS

MAX_COLUMNS

Software resource limit, not a claim about the printer’s capabilities.

Functions

parse_header

Validate header framing and checksum, returning a software-bounded body length. This does not validate the body or assert that a length describes a print job.

set_cassette_type_write

Stand-alone set-cassette-type write for the short-command characteristic: HEADER + ESC s + ESC M <id> 00 00 00 + ESC Q as one non-print write (S2 docs/protocol/letratag-bt.md, “Stand-alone set-cassette-type payload”). The three zero pad bytes are part of the wire format. S1 documents the same command with a 3-byte ESC M and no padding; that variant was never bench-tested (S1’s CLI does not use it), so the S2 form is used.