thermal-label

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Wire Protocols ​

This driver implements two closely related Brother raster protocols. The device's engine.protocol field selects which one applies.

ql-raster — Brother QL family ​

The DK-tape QL series (QL-500 through QL-1115NWB), including the two-colour QL-800 / QL-810W / QL-820NWB models. 720-pin and 1296-pin heads, DK continuous and die-cut media. See QL raster protocol for the full reference.

pt-raster — Brother PT-P / PT-E family ​

The PC-connectable P-touch lineup (PT-E550W, PT-P750W, PT-P900, PT-P900W, PT-P950NW, PT-P910BT). 128-pin or 560-pin heads, TZe laminated tape and HSe heat-shrink tubing. Same outer command shape as QL, with a smaller feed margin, a different high-resolution flag bit, and per-line raster duplication in high-res mode. See PT raster protocol for the deltas.

Shared building blocks ​

Both protocols use:

  • The same status request (1B 69 53 / ESC i S) and 32-byte response layout.
  • The same 0x67 single-plane raster row opcode and (for two-colour QL only) 0x77 dual-plane opcode.
  • The same TIFF/PackBits compression scheme.
  • The same end-of-job rule: 0x0C between pages, 0x1A after the last.

The encoder lives in packages/core/src/protocol.ts. Per-protocol constants (feedMarginDots, invalidateBytes, highResFlagBit, duplicateRasterLines) live in QL_PROTOCOL_CONFIG and PT_PROTOCOL_CONFIG at the top of that file.