Brother QL/PT protocol and implementation details

[matthijskooijman]

The driver for the brother QL/PT protocol is in progress and slowly starting to work, see also #15 and #167. The latter PR triggered a bit of followup discussion about the implementation and the protocol, but it is probably good to keep that in more central place, like here. There is also a wiki page to collect the results of discussion here.

[matthijskooijman]

@michaelrsweet on the wiki, you wrote:

PT-series notes:
High resolution is 720x360dpi, normal resolution is 360dpi

What did you base this on? For my PT-E550W it is 360x180dpi or 180x180dpi.

About cutting:

• ESC i K, bit 3 is the no chain printing / cut at end bit which controls cutting at the end
• ESC i M, bit 6 is the auto-cut bit which controls cutting before the first label
• ESC i A sets "cut every x labels", which I presume controls printing between multiple pages (not tested yet)
• ESC i K, bit 2 is the half-cut bit, which enables cutting just the label and not the backing tape (not tested yet)
• ESC i K, but 4 is the special tape, do not cut bit.

What is not clear from the docs (and I have not tested this yet), is:

• Does half-cut affect all cuts, or maybe just cuts between pages?
• If you change the half-cut bit between multiple pages, can you do half-cutting on some cuts but not others?
• Does the auto-cut bit control just the first cut, or also between-page cuts?
• Does the special tape bit do anything else than prevent cutting? Does it prevent all cutting (and make the other cutting bits no-ops)?

[michaelrsweet]

I'm basing that on the documentation for the PT-P900 series printers I have from Brother's web site. I haven't slogged through all of the manuals yet (I have two other PT manuals for different models, plus four QL manuals covering various models...) so I'm sure there are other changes I'll need to make.

For reference, I have the PT-P700 and QL-600 printers in my home office...

[andreas-gruenbacher]

Take the documentation with a grain of salt; not everything in there is correct and a fair amount of experimentation will be needed. As bad as it may be, the old driver contains bits and pieces of information about things already tried in the source code and in commit messages.

I've got a PT-P900W and a QL-820NWB.

[matthijskooijman]

I'm hoping to make some progress again on this project this summer, see if we can get the driver in a more working shape.

For reference, I have a PT-E550W and a QL-560.