DST (Data Stitch Tajima) is a very commonly-used proprietary embroidery format originally from Tajima. The files contain only stitch commands for the embroidery machines. And a metadata information of label. It is not very nicely designed but because of its age (it came about from punchcard days) but the general ubiquity means it is as close to a standard as exists within embroidery. Some format changes are made such as to not affect the reading by embroidery machines and yet have the ability to be interpreted different on newer machines with newer functionality.

• DST files have a maximum stitch/jump length of 121.
• DST files contain metadata element: label
• DST files do not contain colors.
• DST files do not contain vectors.
• DST files do not contain thumbnails.

Each file consists of two parts: a header, and a body.

Header[edit | edit source]

DST headers are always 512 bytes long. These headers only actually use 125 bytes of data that is actually expected. When reading a dst file these can be safely entirely skipped as only the label would contain any information that might not exist otherwise or be more safely recalculated from the file itself. While this document does include references to other bits of metadata that might be critical like thread colors or author, those are so rare as to be ignorable.

The best explanation of the header information is from the Embroidermodder source code:

"The header seems to contain information about the design. Seems to be ASCII text delimited by 0x0D (carriage returns). This must be in the file for most new software or hardware to consider it a good file! This is much more important than I originally believed. The header is 125 bytes in length and padded out by 0x20 to 512 bytes total. All entries in the header seem to be 2 ASCII characters followed by a colon, then it's (sic) value trailed by a carriage return."

Do note that when writing these *are* required. Some machines do load up the first aspects of these to calculate things like percent complete for the file by counting the process stitches and using ST as the total. And may do things like using the extends to calculate whether it fits in the hoop, rather than recalculating these from reprocessing the stitches. However, AX, AY, MX, and MY are almost always set to zero and PD always to "******".

Additional headers[edit | edit source]

There are some DST files that contain some additional header information of arbitrary size:

These are exceptionally rare. It is unknown what would make files with these metadata tags. However these extensions would allow DST files to contain proper thread information simply adding on a reference for each thread color as needed. The actual used header within DSTs is 125 out of the 512 byte static size header so there is clearly 387 bytes of nothing in most files. Using these seems to be pretty easy expansion.

Example[edit | edit source]

LA:sequin3

ST: 685 CO: 1

+X: 270

-X: 270

+Y: 224

-Y: 224

AX:+ 0

AY:+ 0

MX:+ 0

MY:+ 0

PD:******

You will notice that AX and AY is nearly always 0, MX and MY are also zero. PD is typically just six asterixis. Most of these fields are not used. However, label is almost always read and stitches is read quite often by machines to calculate how far through the design the current embroidery is. The extends might also be used to calculate whether the design will properly fit within the hoop.

Body[edit | edit source]

DST commands are always 3 bytes long. Most other embroidery formats are 2 bytes long with special commands using two additional bytes.

The earliest decoding of the stitches from DST seems to appear on http://www.achatina.de/sewing/main/TECHNICL.HTM

Control Codes[edit | edit source]

While the author of that early decoding interpreted c0 and c1 as "jump" and "color change" it's actually a bit more complicated.

So STOP and COLOR_CHANGE are the same command. Usually machines indicate a stop rather than a color change by color-changing to the same needle.

END command[edit | edit source]

The end of an embroidery file often are seen as having an END command. In DST this is just a STOP. At least it is for programs like EO. With modern filesystems you can know that a file has ended when you reach the end of the file and do not read beyond the file size. However prior to this with punch cards there might not have been any particular way to know this easily. Wilcom output for DST files ends with 0x1A. It is unknown if this is a compatibility thing for some embroidery machine out there or why it exists or whether it should be duplicated.

As an aside: this does interestingly mean that you can detect any Wilcom DST file by filesize alone. Namely all DST files are going to have ((file_size - 512) % 3) == 0. With Wilcom this will be ((file_size - 512) % 3) == 1

TRIM command[edit | edit source]

TRIM command is assumed to exist after a set number of jump commands in a row. This is often 3 but could be as high as 5. In order to ensure the machine that a the embroidery machine trims appropriately it is conventional to insert several small fake jumps such as +2 +2, -4 -4, +2 +2 which results in going nowhere, but hits the jump limit on the machine and requires it to trim.

SEQUIN command[edit | edit source]

The Sequin command appears to turn on and off sequin mode. In that when the sequin command is issued, it thereafter interprets the JUMP command as an EJECT command for drop a sequin in this position.

See Also[edit | edit source]

• https://community.kde.org/Projects/Liberty/File_Formats/Tajima_Ternary
• http://www.achatina.de/sewing/main/TECHNICL.HTM