Interoperability

@thermal-label/tspl-core is a generic TSPL II encoder. The byte sequences it emits are sourced exclusively from TSC's TSPL II Programming Manual — the canonical reference published by TSC for the TSPL II command stream.

What this package is

A pure-protocol encoder. Every byte it produces is documented in TSC's manual; nothing in this package is reverse-engineered from a specific firmware build.

This is the opposite of a "driver" — it does not know about transports, device IDs, or vendor quirks. It knows about TSPL II the language.

What this package is not

• It is not a vendor-specific driver. It does not target a particular brand or model.
• It is not a hardware-verified compatibility list. Driver packages built on top of it own that.
• It does not include vendor extensions that some firmwares layer on top of TSPL II — LZO-compressed BITMAP modes 3/4, ACK framing, vendor <KEY>:<VALUE> status reply schemas, AT-command bridges. Those belong in driver packages.

Compatibility scope

If a printer accepts the directive set described in TSC's TSPL II Programming Manual, tspl-core can produce a job for it. This includes TSC's own consumer and industrial lines as well as the many third-party firmwares that license or re-implement TSPL II.

Specific quirks (bit polarity inversion, line-ending preferences, required preamble bytes, vendor-only directives) are the driver package's concern. tspl-core provides the spec-aligned baseline; drivers extend it.

Source attribution

The single source for every byte emitted by this package is TSC's TSPL II Programming Manual.

There is intentionally no harvesting from any vendor's mobile app, firmware, Linux CUPS driver, or proprietary SDK. Driver packages are free to do that work for their own targets, but tspl-core stays anchored on the published spec so that consumers can rely on its bytes matching TSC's documentation byte-for-byte.

Bit polarity note

The TSC TSPL II manual specifies that within a BITMAP payload, bit 0 represents a printed (dark) dot and bit 1 represents an un-printed dot. This is the opposite of the convention used by most in-memory bitmap libraries (including @mbtech-nl/bitmap, which uses 1 = dark).

encodeTsplJob applies a per-byte one's-complement to bridge the two conventions: feed it a LabelBitmap, get out spec-aligned wire bytes. Vendor packages whose firmware accepts the inverted-from-spec polarity should bypass encodeTsplJob and call the directive builders directly — their bitmap data goes on the wire raw.

Future direction

The package surface is intentionally small and stable. Additions will be limited to directives newly documented by TSC. Vendor extensions are explicitly out of scope and will not be merged into the public API even on request.