How to decode ARINC 429 data?
ARINC 429 is a defined standard that not only describes the packet structure (32 bits) but also the data formats for different labels depending on the equipment ID. To know how to properly decode an ARINC 429 label you need to know the Equipment ID, which can then be used to look up the meaning of a specific label.

The manufacturer of the device that the data came from may also provide the definition of any non-standard/custom labels

If you know which labels you are looking for you don't have to decode the entire label, you just need to inspect the bits 8-1 to determine the label.

In general though, the ARINC 429 specification provides a guideline for labels:


  Binary coded decimal (BCD) sub-group 001 to 067, 125, 165, 170, 200, 201,230 to 237.
  
  Binary (BNR) subgroup 070 to 124, 126 to 144, 150 to 154, 162 to 164, 166, 167, 171 to 177, 202 to 227, 240 to
  257, 262 to 265, 267, 310 to 347, 360 to 376.
  
  Mixed BCD and BNR subgroup 260, 261
  
  Discretes subgroup 145 to 147, 270 to 276
  
  Maintenance and discrete data subgroup 155, 156
  
  Maintenance data subgroup 157 to 161, 350 to 354
  
  Test word subgroup 266, 277
  
  Application dependent subgroups 300 to 307
  
  Acknowledgement subgroup 355
  
  Maintenance ISO #5 subgroup 356
  
  ISO #5 message subgroup 357