Phonetics has three functions: Description(describes how sounds are produced), classification(classifies sounds into consonants and vowels), and transcription(represents speech sounds with symbols).

Phonetics has three types/branches: Articulatory, acoustic, and auditory phonetics.

I have difficulty understanding the relationship between the functions of phonetics and its branches.
In other words, which branch deals with which function?

Does articulatory phonetics alone deal with the three functions? How is that?

Thanks a lot.