diff --git a/doc/audio-api.txt b/doc/audio-api.txt
index a73ba20..b19e10f 100644
--- a/doc/audio-api.txt
+++ b/doc/audio-api.txt
@@ -195,3 +195,116 @@ properties boolean Connected [readonly]
Indicates if a stream is active to a A2DP sink on
the remote device.
+
+
+Gateway hierarchy
+===================
+
+Service org.bluez
+Interface org.bluez.HeadsetGateway
+Object path [variable prefix]/{hci0,hci1,...}/dev_XX_XX_XX_XX_XX_XX
+
+This interface is available for remote devices which can function in the Audio
+Gateway role of the HFP profiles.
+
+Methods void Connect()
+
+ Connect to the AG service on the remote device.
+
+ void Disconnect()
+
+ Disconnect from the AG service on the remote device
+
+ void AnswerCall()
+
+ It has to called only after Ring signal received.
+
+ void TerminateCall()
+
+ Terminate call which is running now. This has nothing
+ with any 3-way situation incl. RaH. Just plain old PDH.
+
+ void Call(string number)
+
+ Dial a number 'number'. No number processing is done
+ thus if AG would reject to dial it don't blame me :)
+
+ string GetOperatorName()
+
+ Find out the name of the currently selected network
+ operator by AG.
+
+ void SendDTMF(string digits)
+
+ Will send each digit in the 'digits' sequentially. Would
+ send nothing if there is non-dtmf digit.
+
+ string[] GetSubscriberNumbers()
+
+ Get all the subscriber numbers of AG
+
+ dict GetProperties()
+
+ Returns all properties for the interface. See the
+ properties section for available properties.
+
+Signals void Ring(string number)
+
+ Someone's calling from 'number'.
+ Caller number is provided as received from AG.
+
+ void CallTerminated()
+
+ Call failed to set up. It means that we tried to call
+ someone or someone tried to call us but call was not
+ accepted.
+
+ void CallStarted()
+
+ Call set up successfully.
+
+ void CallEnded()
+
+ Call was started and now ended. In contrast with
+ CallTerminated where call didn't started
+
+ PropertyChanged(string name, variant value)
+
+ This signal indicates a changed value of the given
+ property.
+
+properties boolean Connected [readonly]
+
+ Indicates if there is an active connection to the
+ AG service on the remote device.
+
+ uint16 RegistrationStatus [readonly]
+
+ Service availability indicatior of AG, where:
+ 0 implies no service. No Home/Roam network available.
+ 1 implies presense of service. Home/Roam network
+ available.
+
+ uint16 SignalStrength [readonly]
+
+ Signal strength indicator of AG, the value ranges from
+ 0 to 5.
+
+ uint16 RoamingStatus [readonly]
+
+ Roaming status indicator of AG, where:
+ 0 means roaming is not active
+ 1 means a roaming is active
+
+ uint16 BatteryCharge [readonly]
+
+ Battery Charge indicator of AG, the value ranges from
+ 0 to 5.
+
+ uint16 SpeakerGain [readonly]
+
+ The speaker gain when available.
+
+ uint16 MicrophoneGain [readonly]
+
+ The speaker gain when available.