Check a pair of traces

Use this to look at a pair before ingesting it, or to check files you received from a contractor. It needs no database and stores nothing.

Before you start

• Two .sor files of the same fibre, one measured from each end, at the same wavelength.

Steps

1. Give the trace measured from end A first, then the one from end B:

   $ asbuilt sor pair fixtures/projects/ee-demo/traces/c1_f01_1550_ab.sor fixtures/projects/ee-demo/traces/c1_f01_1550_ba.sor
   …
     "findings": [],
   …
     "status": "PASS",
     "tol_m": 5.245,
     "total_loss_db": 0.297,
     "unpaired_ab": [],
     "unpaired_ba": []
   }
   

2. Read the result:

   Field	Tells you
   status	PASS or FAIL for the pair.
   findings	Every problem, with its code and a message naming the event and its losses.
   paired	Each event seen from both ends: its distance, its loss from each end and the averaged loss.
   unpaired_ab, unpaired_ba	Events seen from one end only.
   length_m, tol_m	The fibre length and how far apart the two ends’ lengths may be.
   total_loss_db	The end-to-end loss, averaged over both ends.
   rules	The limits the pair was judged against.

3. The limits default to 0.30 dB per splice, 0.75 dB per connector and −35.0 dB reflectance. To judge with a project’s own limits, give them: --max-splice-db 0.25.

Check

status is PASS, and findings is empty or holds only warnings you understand.

What can go wrong

You see	Meaning	Do
BIDIR_WAVELENGTH_MISMATCH	The files were measured at different wavelengths.	Pair files of the same wavelength.
BIDIR_LENGTH_MISMATCH	The two ends see fibres of different lengths.	The files are of different fibres or cables.
Many BIDIR_UNPAIRED_EVENT findings and a FAIL	Possibly two different fibres of the same cable: they have the same length, so ruumica cannot tell them apart by length.	Check the fibre numbers in both files.