I have been looking for ACARS documentation and blogs to understand the different message label types with no luck so far. i do understand though that standardization is not really being followed and each airline/aircraft manufacturer can come up with their own and not sharing it to public. BUT at least there should be a list of standard labels for interoperability, right? eg Q0 for link test or B9 for ATIS information Request.
does anyone have such a list and willing to share with this community?