They give personal details in depth (1-4)
I believe the answer is:
x-rays
'details in depth' is the definition.
The definition and answer can be both to do with communicating as well as being verbs in their -s form.
Perhaps there's a link between them I don't understand?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for x-rays that I've seen before include "Penetrating radiation" , "Hospital photos" , "Photos or exams made with kind of radiation" , "'Electromagnetic waves, for medical diagnosis say (1-4)'" , "Short-wavelength radiation" .)