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+++ b/README.md
@@ -27,6 +27,20 @@ Starting from an existing instrument made in PureData :
 4. Create a bf-param object for each control you want to share with the others and insert it into your instrument
 5. Create a bf-session object with the name of the session you want to connect to
 
+### Parameters and outputs
+
+**Parameters** correspond to controls you have over your instrument and that you want to share with others.
+They can have 1 or more values, and can be of multiple types :
+
+* cont : continuous value between 0 and 1
+* midi : discrete value between 0 and 127
+* bool : 0/1 value
+* bang 
+
+**Outputs** have the same properties but correspond to musical content produced by your instruments (notes, onsets, envelopes ...). They can be used to control others parameters.
+Three default outputs are automatically created by bf-pd and extracted from the audio you send to bf-instrument : pitch, onsets, loudness.
+
+
 ## Performance: Making music together using bf-pd
 
 ### The collaboration window