diff --git a/src/energenie/Devices.py b/src/energenie/Devices.py
index db3397e..a6beee3 100644
--- a/src/energenie/Devices.py
+++ b/src/energenie/Devices.py
@@ -3,15 +3,16 @@
 # Information about specific Energenie devices
 # This table is mostly reverse-engineered from various websites and web catalogues.
 
-#TODO: Might move this into an air_interface adaptor, so that TwoBit encodes
-#are done consistently outside of this module, just like OpenThings encodes and decodes are.
-#They are done externally, because you need the address before you can route it to these classes.
-#import TwoBit
+import OnAir
+
+# This level of indirection allows easy mocking for testing
+ook_interface = OnAir.TwoBitAirInterface()
+fsk_interface = OnAir.OpenThingsAirInterface()
+
 
 MFRID_ENERGENIE                  = 0x04
 MFRID                            = MFRID_ENERGENIE
 
-
 #PRODUCTID_MIHO001               =        #         Home Hub
 #PRODUCTID_MIHO002               =        #         Control only (Uses Legacy OOK protocol)
 #PRODUCTID_MIHO003               = 0x0?   #         Hand Controller
@@ -97,18 +98,16 @@
 # this might be a real air_interface (a radio), or an adaptor interface
 # (a message scheduler with a queue).
 #
-# TODO: As such, we need to handle:
 #   synchronous send
 #   synchronous receive
-#   asynchronous send (deferred)
-#   asynchronous receive (deferred)
+#   TODO: asynchronous send (deferred)    - implies a callback on 'done, fail, timeout'
+#   TODO: asynchronous receive (deferred) - implies a callback on 'done, fail, timeout'
 
 # air_interface has:
 #   configure(parameters)
 #   send(payload)
 #   send(payload, parameters)
-#   listen(parameters)
-#   check() -> payload or None
+#   receive() -> (radio_measurements, address, payload)
 
 
 #----- NEW DEVICE CLASSES -----------------------------------------------------
@@ -170,8 +169,8 @@
 
 class LegacyDevice(EnergenieDevice):
     """An abstraction for Energenie green button legacy OOK devices"""
-    def __init__(self, air_interface):
-        EnergenieDevice.__init__(self, air_interface)
+    def __init__(self):
+        EnergenieDevice.__init__(self, ook_interface)
         self.config.frequency  = 433.92
         self.config.modulation = "OOK"
         self.config.codec      = "4bit"
@@ -199,8 +198,8 @@
 
 class MiHomeDevice(EnergenieDevice):
     """An abstraction for Energenie new style MiHome FSK devices"""
-    def __init__(self, air_interface, device_id=None):
-        EnergenieDevice.__init__(self, air_interface, device_id)
+    def __init__(self, device_id=None):
+        EnergenieDevice.__init__(self, fsk_interface, device_id)
         self.config.frequency  = 433.92
         self.config.modulation = "FSK"
         self.config.codec      = "OpenThings"
@@ -261,8 +260,8 @@
 
 class ENER002(LegacyDevice):
     """A green-button switch"""
-    def __init__(self, air_interface=None, device_id=None):
-        LegacyDevice.__init__(self, air_interface)
+    def __init__(self, device_id=None):
+        LegacyDevice.__init__(self)
         self.device_id = device_id # (house_address, device_index)
         self.config.tx_repeats = 8
         self.capabilities.switch = True
@@ -277,8 +276,8 @@
 
 class MIHO005(MiHomeDevice):
     """An Energenie MiHome Adaptor Plus"""
-    def __init__(self, air_interface=None, device_id=None):
-        MiHomeDevice.__init__(self, air_interface)
+    def __init__(self, device_id=None):
+        MiHomeDevice.__init__(self)
         self.product_id = PRODUCTID_MIHO005
         self.device_id  = device_id
         class Readings():
@@ -354,8 +353,8 @@
 
 class MIHO006(MiHomeDevice):
     """An Energenie MiHome Home Monitor"""
-    def __init__(self, air_interface=None, device_id=None):
-        MiHomeDevice.__init__(self, air_interface)
+    def __init__(self, device_id=None):
+        MiHomeDevice.__init__(self)
         self.product_id = PRODUCTID_MIHO006
         self.device_id  = device_id
         class Readings():
@@ -373,8 +372,8 @@
 
 class MIHO013(MiHomeDevice):
     """An Energenie MiHome eTRV Radiator Valve"""
-    def __init__(self, air_interface=None, device_id=None):
-        MiHomeDevice.__init__(self, air_interface)
+    def __init__(self, device_id=None):
+        MiHomeDevice.__init__(self)
         self.product_id = PRODUCTID_MIHO013
         self.device_id  = device_id
         class Readings():
diff --git a/src/energenie/OnAir.py b/src/energenie/OnAir.py
index 8e39284..00ca7e8 100644
--- a/src/energenie/OnAir.py
+++ b/src/energenie/OnAir.py
@@ -17,81 +17,146 @@
 import TwoBit
 import radio
 
+def log_method(m):
+    def inner(*args, **kwargs):
+        print("CALL %s with %s %s" % (m, args, kwargs))
+        r = m(*args, **kwargs)
+        print("RETURN %s with %s" % (m, r))
+        return r
+    return inner
+
 
 class OpenThingsAirInterface():
     def __init__(self):
         self.radio = radio # aids mocking later
-        #TODO: tx defaults
-        # FSK, inner_repeats, outer_delay, outer_repeats, power_level, frequency
-        #TODO: rx defaults
-        # FSK, poll_rate, timeout, frequency
 
+        class RadioDefaults():
+            frequency     = 433.92
+            modulation    = radio.RADIO_MODULATION_FSK
+
+        class TxDefaults(RadioDefaults):
+            power_level   = 0
+            inner_repeats = 4
+            outer_delay   = 0
+            outer_repeats = 0
+        self.tx_defaults = TxDefaults()
+
+        class RxDefaults(RadioDefaults):
+            poll_rate     = 100  #ms
+            timeout       = 1000 #ms
+        self.rx_defaults = RxDefaults()
+
+    @log_method
     def send(self, payload, radio_params=None):
         #   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
         pass #TODO
-        #TODO: OpenThings.encode()
-        #TODO: configure radio modulation
-        #TODO: set radio to transmit mode
+        p = OpenThings.encode(payload)
+        #TODO: merge radio_params with self.tx_defaults
+        #TODO: configure radio modulation based on merged params
+        radio.transmitter(fsk=True)
         #TODO: configure other radio parameters
         #TODO: transmit payload
-        #TODO: return radio to state before transmit
+        radio.transmit(p, outer_times=0, inner_times=4, outer_delay=0)
+        # radio auto-returns to previous state after transmit completes
 
+    @log_method
     def receive(self, radio_params): # -> (radio_measurements, address or None, payload or None)
         #   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
         pass # TODO
-        #TODO: configure radio modulation
         #TODO: set radio to receive mode
-        #TODO: set other radio parameters
+        #TODO: merge radio_params with self.tx_defaults
+        #TODO: configure radio modulation based on merged params
+
         #TODO: poll radio at rate until timeout or received
-        #TODO: return radio to state it was before receive
-        #TODO: OpenThings.decode
-        #TODO: report damaged payload (crc failure)
-        #TODO: extract addresses
-        #TODO: return (radio_measurements, address, payload)
+        #TODO: start timeout timer
+        payload = None
+        radio.receiver(fsk=True)
+        while True: # timer not expired
+            if radio.is_receive_waiting():
+                payload = radio.receive() # TODO payload, radio_measurements = radio.receive()
+                p = OpenThings.decode(payload)
+                #TODO: if crc failure, report it, but keep trying
+                #if crc check passes...
+                break
+            #TODO: inter-try delay
+        #TODO: return radio to state it was before receiver (e.g. standby) - radio needs a pop() on this too?
+
+        if payload == None: # nothing received in timeout
+            return (None, None, None) # (radio_measurements, address, payload) # TODO: might be measurements, average min max?
+
+        #TODO: extract addresses: header_manufacturerid, header_productid header_deviceid -> (m, p, d)
+        m, p, d = None, None, None
+        radio_measurements = None # TODO get from radio.receive()
+        address = (m, p, d)
+        return (radio_measurements, address, payload)
 
 
 class TwoBitAirInterface():
     def __init__(self):
         self.radio = radio # aids mocking later
-        #TODO: tx defaults
-        # OOK, inner_repeats, outer_delay, outer_repeats, power_level, frequency
-        #TODO: rx defaults
-        # OOK, poll_rate, timeout, frequency
 
+        class RadioDefaults():
+            frequency     = 433.92
+            modulation    = radio.RADIO_MODULATION_OOK
+
+        class TxDefaults(RadioDefaults):
+            power_level   = 0
+            inner_repeats = 8
+            outer_delay   = 0
+            outer_repeats = 0
+        self.tx_defaults = TxDefaults()
+
+        class RxDefaults(RadioDefaults):
+            poll_rate     = 100  #ms
+            timeout       = 1000 #ms
+        self.rx_defaults = RxDefaults()
+
+    @log_method
     def send(self, payload, radio_params=None):
         #   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
-        pass #TODO
 
-        #TODO: TwoBit.encode()
-        #TODO: configure radio modulation
-        #TODO: set radio to transmit mode
-        #TODO: configure other radio parameters
+        p = TwoBit.encode(payload)
+        radio.modulation(ook=True)
+        #TODO: merge radio_params with self.tx_defaults
+        #TODO: configure radio modulation based on merged params
         #TODO: transmit payload
-        #TODO: return radio to state before transmit
+        radio.transmit(p, outer_times=1, inner_times=8, outer_delay=0) #TODO: radio params
+        # radio auto-pops to state before transmit
 
+    @log_method
     def receive(self, radio_params): # -> (radio_measurements, address or None, payload or None)
         #   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
-        pass # TODO
-        #TODO: configure radio modulation
-        #TODO: set radio to receive mode
-        #TODO: set other radio parameters
+        #TODO: merge radio_params with self.tx_defaults
+        #TODO: configure radio modulation based on merged params
+
         #TODO: poll radio at rate until timeout or received
-        #TODO: return radio to state it was before receive
-        #TODO: TwoBit.decode
-        #TODO: report damaged payload??
+        #TODO: start timeout timer
+        payload = None
+        radio.receiver(ook=True)
+        while True: # timer not expired
+            if radio.is_receive_waiting():
+                #TODO: radio config should set receive preamble 4 bytes to prevent false triggers
+                payload = radio.receive(size=12) # TODO payload, radio_measurements = radio.receive()
+                p = TwoBit.decode(payload)
+                #TODO: if failure, report it, but keep trying
+                #if  check passes...
+                break
+            #TODO: inter-try delay
+        #TODO: return radio to state it was before receiver (e.g. standby) - radio needs a pop() on this too?
+
+        if payload == None: # nothing received in timeout
+            return (None, None, None) # (radio_measurements, address, payload) # TODO: might be measurements, average min max?
+
         #TODO: extract addresses (house_address, device_index)
-        #TODO: return (radio_measurements, address, payload)
+        radio_measurements = None #TODO: return this from radio.receive()
+        h = 0xC8C8C #TODO: Get house address from TwoBit.decode()[:10]
+        d = 0xEE    #TODO: Get device command from TwoBit.decode()[11:12]
+        address = (h, d)
+        return (radio_measurements, address, payload)
 
 
 # END
diff --git a/src/energenie/TwoBit.py b/src/energenie/TwoBit.py
index 484a914..283373a 100644
--- a/src/energenie/TwoBit.py
+++ b/src/energenie/TwoBit.py
@@ -58,6 +58,7 @@
     return line
 
 
+#TODO: encode_relay_msg
 def build_relay_msg(relayState=False):
     """Temporary test code to prove we can turn the relay on or off"""
 
@@ -72,6 +73,7 @@
     return payload
 
 
+#TODO: encode_test_message
 def build_test_message(pattern):
     """build a test message for a D3D2D1D0 control patter"""
     payload = PREAMBLE + DEFAULT_ADDR_ENC
@@ -81,6 +83,7 @@
     return payload
 
 
+#TODO: encode_switch_msg
 def build_switch_msg(state, device_address=ALL_SOCKETS, house_address=None):
     """Build a message to turn a switch on or off"""
     #print("build: state:%s, device:%d, house:%s" % (str(state), device_address, str(house_address)))
@@ -133,6 +136,7 @@
     #print("encoded as:%s" % ashex(payload))
     return payload
 
+#TODO: decode_switch_msg
 
 def encode_bytes(data):
     """Turn a list of bytes into a modulated pattern equivalent"""
@@ -165,5 +169,22 @@
     return encoded
 
 
+#TODO: decode_bytes
+
+#TODO: decode_bits
+
+#TODO: decode_command
+# 0, False  (all off)
+# 0, True   (all on)
+# 1, False  (1 off)
+# 1, True   (1 on)
+# 2, False  (2 off)
+# 2, True   (2 on)
+# 3, False  (3 off)
+# 3, True   (3 on)
+# 4, False  (4 off)
+# 4, True   (4 on)
+# UNKNOWN   (6 of the other patterns, that are not recognised)
+
 # END