Barudan U01 and Tajima TBF: the commercial formats that carry needle numbers

DST tells a commercial machine where to sew. It does not say with which needle, or what colour is on it, so every DST run starts with the operator setting the needle sequence from a sheet. Two formats fix that for the two biggest commercial brands: Barudan's U01 and Tajima's TBF. Both keep the DST idea (small records, no objects) and add what a busy shop wants.

U01 (Barudan)

U01 is a member of a family: U00, U01 and U02 differ only in the header's version field. The file is a 256-byte header (design name, stitch count, extents) followed by three-byte records. The first byte is the command, the next two the move.

The important commands are the needle changes: values 0x09 to 0x17 mean "change to needle 1" through "change to needle 15". A U01 does not have a generic colour change at all; every change names the needle. The machine reads the number and moves its needle bar there, so the sequence is in the file and the operator loads it and presses start.

Other command bits mark jumps, trims (a dedicated command, unlike DST's three-jump convention), and the speed flags: fast and slow, which Barudan machines use to slow down on long stitches or dense areas. A stop for applique is its own command. The viewer decodes the needle numbers and shows the blocks as "needle 3, 1,240 stitches", which is what the file says and what the machine will do.

What U01 does not carry: colours. Needle 3 is needle 3; what thread is on it is the shop's business, recorded on the colour sheet.

TBF (Tajima)

TBF is Tajima's replacement for DST, read by every Tajima made since the late 1990s and by their software. A TBF starts with a text header of key-value lines, like DST's but longer: label (LA), stitch and colour counts (ST, CO), extents, the version string 3.00, and two lines that DST lacks: DO, the needle order as a list of needle numbers for each colour block, and DA, a list of RGB values for the threads on those needles.

Stitch records are three bytes with the same ternary-style encoding as DST, so a converter between the two only changes the header and the colour-change semantics: in TBF, a colour change is still a stop-type record, but the DO line tells the machine which needle each stop advances to.

Because DA carries RGB, a TBF converted to PES or VP3 keeps its colours (approximately, through the target's palette). A TBF written from PES carries the PES palette's RGB in DA and a default needle order 1, 2, 3 in DO, which the operator can accept or edit on the machine.

When to use them

Use DST when the file is going to a machine you do not control, or to a digitiser, or is being sold. Everyone reads it.

Use U01 or TBF when the same shop runs the same designs repeatedly on Barudan or Tajima heads and wants the needle sequence to travel with the file. The gain is a minute per design load and the errors it prevents; on a floor doing 30 design changes a day, that is a real hour.

Do not use them to carry a design to a different brand of machine. A Barudan does not read TBF and a Tajima does not read U01. Convert to DST for that, and accept setting the needles.

Converting

DST → U01. Each colour change becomes "next needle": the writer assigns needles 1, 2, 3 in order, starting again at 1 after the machine's needle count (15 by default). Trims from the three-jump convention become U01 trim commands. Long stitches are already within the 12.1 mm limit. The DST to U01 page has the specifics.

DST → TBF. The header gains DO (needles in order) and DA (colours, defaults if the DST had none). Stitches are copied. DST to TBF.

PES/JEF/VP3 → U01 or TBF. Colours: TBF keeps them in DA; U01 drops them. Trims: both formats have explicit trims, written where the source had them or at long jumps. Needles: assigned in block order.

U01 or TBF → PES/DST. Needle changes become colour changes. A design that used needle 3 then needle 3 again (two blocks, same needle) becomes two blocks in the target; cleanup can merge them if the same colour is intended.

Our writers for both formats are byte-identical to pyembroidery's on the corpus we tested, so a file written here matches what the reference library writes; the converter lists the specific losses for each pair before you download.

Reading a needle-addressed file

The viewer's block list shows the needle for each block; if two blocks show the same needle in a row, the file has a stop with no needle change, usually an applique stop or a "check the thread" pause the digitiser put in. The colour sheet should say why. If it does not, ask before running 200 pieces.