diff --git a/src/energenie/OnAir.py b/src/energenie/OnAir.py
index c9e795c..86ecaa7 100644
--- a/src/energenie/OnAir.py
+++ b/src/energenie/OnAir.py
@@ -16,20 +16,39 @@
 class OpenThingsAirInterface():
     pass
 
-    # tx, pydict payload and radio params in
-    # OpenThings encode and encrypt, configure radio for FSK transmit, pass repeats
-    
-    # rx, configure radio for FSK receive OpenThings decode and decrypt,
-    # pydict payload and metadata (RSSI etc) out
+    # init
+    #   radio params defaults FSK, inner_repeats, outer_delay, outer_repeats, power_level, frequency
+
+    # send(payload, radio_params)
+    #   payload is a pydict suitable for OpenThings
+    #   radio_params is an overlay on top of radio tx defaults
+    #   tx, pydict payload and radio params in
+    #   OpenThings encode and encrypt, configure radio for FSK transmit, pass repeats
+
+    # receive(radio_params) #-> (radio_measurements) or (radio_measurements, payload)
+    #   radio_params is an overlay on top of radio rx defaults (e.g. poll rate, timeout, min payload, max payload)
+    #   radio_measurements might include rssi reading, short payload report, etc
+    #   rx, configure radio for FSK receive OpenThings decode and decrypt,
+    #   pydict payload and metadata (RSSI etc) out
 
 
 class TwoBitAirInterface():
     pass
-    # tx, pydict payload and radio params in
-    # TwoBit encode, configure radio for OOK transmit, pass repeats
 
-    # rx, configure radio for OOK receive, TwoBit decide
-    # pydict payload and metadata (RSSI etc) out
+    # init
+    #   radio params defaults OOK, inner_repeats, outer_delay, outer_repeats, power_level, frequency
+
+    # send(payload, radio_params)
+    #   payload is just a list of bytes, or a byte buffer
+    #   radio_params is an overlay on top of radio tx defaults
+    #   tx, pydict payload and radio params in
+    #   TwoBit encode, configure radio for OOK transmit, pass repeats
+
+    # receive(radio_params) #-> (radio_measurements) or (radio_measurements, payload)
+    #   radio_params is an overlay on top of radio rx defaults (e.g. poll rate, timeout, min payload, max payload)
+    #   radio_measurements might include rssi reading, short payload report, etc
+    #   rx, configure radio for OOK receive, TwoBit decode
+    #   pydict payload and metadata (RSSI etc) out
 
 
 # END