diff --git a/src/com/android/services/telephony/CdmaConference.java b/src/com/android/services/telephony/CdmaConference.java
old mode 100755
new mode 100644
index 693fd16..32badd0
--- a/src/com/android/services/telephony/CdmaConference.java
+++ b/src/com/android/services/telephony/CdmaConference.java
@@ -73,6 +73,16 @@
     }
 
     @Override
+    public void onAnswer(int videoState) {
+        Log.e(this, new Exception(), "Answer not supported for CDMA conference call.");
+    }
+
+    @Override
+    public void onReject() {
+        Log.e(this, new Exception(), "Reject not supported for CDMA conference call.");
+    }
+
+    @Override
     public void onHold() {
         Log.e(this, new Exception(), "Hold not supported for CDMA conference call.");
     }
diff --git a/src/com/android/services/telephony/ImsConference.java b/src/com/android/services/telephony/ImsConference.java
index 4c3f9c9..4649d23 100644
--- a/src/com/android/services/telephony/ImsConference.java
+++ b/src/com/android/services/telephony/ImsConference.java
@@ -199,6 +199,18 @@
                     TelephonyConnection telephonyConnection = (TelephonyConnection) c;
                     handleConferenceParticipantsUpdate(telephonyConnection, participants);
                 }
+
+                /**
+                 * Handles request to play a ringback tone.
+                 *
+                 * @param c The connection.
+                 * @param ringback Whether the ringback tone is to be played.
+                 */
+                @Override
+                public void onRingbackRequested(android.telecom.Connection c, boolean ringback) {
+                    Log.d(this, "onRingbackRequested ringback %s", ringback ? "Y" : "N");
+                    setRingbackRequested(ringback);
+                }
             };
 
     /**
@@ -224,6 +236,11 @@
     private TelecomAccountRegistry mTelecomAccountRegistry;
 
     /**
+     * The participant with which Adhoc Conference call is getting formed.
+     */
+    private List<Uri> mParticipants;
+
+    /**
      * The known conference participant connections.  The HashMap is keyed by a Pair containing
      * the handle and endpoint Uris.
      * Access to the hashmap is protected by the {@link #mUpdateSyncRoot}.
@@ -383,6 +400,10 @@
         conferenceProperties = changeBitmask(conferenceProperties,
                 Connection.PROPERTY_REMOTELY_HOSTED, !isConferenceHost());
 
+        conferenceProperties = changeBitmask(conferenceProperties,
+                Connection.PROPERTY_IS_ADHOC_CONFERENCE,
+                (properties & Connection.PROPERTY_IS_ADHOC_CONFERENCE) != 0);
+
         return conferenceProperties;
     }
 
@@ -422,6 +443,26 @@
         return VideoProfile.STATE_AUDIO_ONLY;
     }
 
+    public Connection getConferenceHost() {
+        return mConferenceHost;
+    }
+
+    /**
+     * @return The address's to which this Connection is currently communicating.
+     */
+    public final List<Uri> getParticipants() {
+        return mParticipants;
+    }
+
+    /**
+     * Sets the value of the {@link #getParticipants()}.
+     *
+     * @param address The new address's.
+     */
+    public final void setParticipants(List<Uri> address) {
+        mParticipants = address;
+    }
+
     /**
      * Invoked when the Conference and all its {@link Connection}s should be disconnected.
      * <p>
@@ -481,6 +522,28 @@
     }
 
     /**
+     * Invoked when the conference is answered.
+     */
+    @Override
+    public void onAnswer(int videoState) {
+        if (mConferenceHost == null) {
+            return;
+        }
+        mConferenceHost.performAnswer(videoState);
+    }
+
+    /**
+     * Invoked when the conference is rejected.
+     */
+    @Override
+    public void onReject() {
+        if (mConferenceHost == null) {
+            return;
+        }
+        mConferenceHost.performReject();
+    }
+
+    /**
      * Invoked when the conference should be put on hold.
      */
     @Override
@@ -838,7 +901,8 @@
                             + "newParticipantcount=%d", oldParticipantCount, newParticipantCount);
             // If the single party call emulation fature flag is enabled, we can potentially treat
             // the conference as a single party call when there is just one participant.
-            if (mFeatureFlagProxy.isUsingSinglePartyCallEmulation()) {
+            if (mFeatureFlagProxy.isUsingSinglePartyCallEmulation() &&
+                    !mConferenceHost.isAdhocConferenceCall()) {
                 if (oldParticipantCount != 1 && newParticipantCount == 1) {
                     // If number of participants goes to 1, emulate a single party call.
                     startEmulatingSinglePartyCall();
@@ -1173,11 +1237,13 @@
         switch (state) {
             case Connection.STATE_INITIALIZING:
             case Connection.STATE_NEW:
-            case Connection.STATE_RINGING:
                 // No-op -- not applicable.
                 break;
+            case Connection.STATE_RINGING:
+                setConferenceOnRinging();
+                break;
             case Connection.STATE_DIALING:
-                setDialing();
+                setConferenceOnDialing();
                 break;
             case Connection.STATE_DISCONNECTED:
                 DisconnectCause disconnectCause;
@@ -1198,10 +1264,10 @@
                 destroyTelephonyConference();
                 break;
             case Connection.STATE_ACTIVE:
-                setActive();
+                setConferenceOnActive();
                 break;
             case Connection.STATE_HOLDING:
-                setOnHold();
+                setConferenceOnHold();
                 break;
         }
     }
diff --git a/src/com/android/services/telephony/ImsConferenceController.java b/src/com/android/services/telephony/ImsConferenceController.java
index 1e10055..98be86e 100644
--- a/src/com/android/services/telephony/ImsConferenceController.java
+++ b/src/com/android/services/telephony/ImsConferenceController.java
@@ -52,8 +52,19 @@
                 Log.v(ImsConferenceController.class, "onDestroyed: %s", conference);
             }
 
+            if (conference instanceof ImsConference) {
+                // Ims Conference call ended, so UE may now have the ability to initiate
+                // an Adhoc Conference call. Hence, try enabling adhoc conference capability
+                mTelecomAccountRegistry.refreshAdhocConference(true);
+            }
             mImsConferences.remove(conference);
         }
+
+        @Override
+        public void onStateChanged(Conference conference, int oldState, int newState) {
+            Log.v(this, "onStateChanged: Conference = " + conference);
+            recalculateConferenceable();
+        }
     };
 
     private final TelephonyConnection.TelephonyConnectionListener mTelephonyConnectionListener =
@@ -101,10 +112,11 @@
     private final ArrayList<TelephonyConnection> mTelephonyConnections = new ArrayList<>();
 
     /**
-     * List of known {@link ImsConference}s.  Realistically there will only ever be a single
-     * concurrent IMS conference.
+     * List of known {@link ImsConference}s. There can be upto maximum two Ims conference calls.
+     * One conference call can be a host conference call and another conference call formed as a
+     * result of accepting incoming conference call.
      */
-    private final ArrayList<ImsConference> mImsConferences = new ArrayList<>(1);
+    private final ArrayList<ImsConference> mImsConferences = new ArrayList<>(2);
 
     private TelecomAccountRegistry mTelecomAccountRegistry;
 
@@ -122,6 +134,17 @@
         mFeatureFlagProxy = featureFlagProxy;
     }
 
+    void addConference(ImsConference conference) {
+        if (mImsConferences.contains(conference)) {
+            // Adding a duplicate realistically shouldn't happen.
+            Log.w(this, "addConference - conference already tracked; conference=%s", conference);
+            return;
+        }
+        mImsConferences.add(conference);
+        conference.addTelephonyConferenceListener(mConferenceListener);
+        recalculateConferenceable();
+    }
+
     /**
      * Adds a new connection to the IMS conference controller.
      *
@@ -250,6 +273,11 @@
                 continue;
             }
 
+            // Since UE cannot host two conference calls, remove the ability to initiate
+            // another conference call as there already exists a conference call, which
+            // is hosted on this device.
+            mTelecomAccountRegistry.refreshAdhocConference(false);
+
             switch (conference.getState()) {
                 case Connection.STATE_ACTIVE:
                     //fall through
@@ -360,6 +388,10 @@
             Log.v(this, "Start new ImsConference - connection: %s", connection);
         }
 
+        if (connection.isAdhocConferenceCall()) {
+            Log.w(this, "start new ImsConference - control should never come here");
+            return;
+        }
         // Make a clone of the connection which will become the Ims conference host connection.
         // This is necessary since the Connection Service does not support removing a connection
         // from Telecom.  Instead we create a new instance and remove the old one from telecom.
diff --git a/src/com/android/services/telephony/PstnIncomingCallNotifier.java b/src/com/android/services/telephony/PstnIncomingCallNotifier.java
index 2dfeaed..46f15b2 100644
--- a/src/com/android/services/telephony/PstnIncomingCallNotifier.java
+++ b/src/com/android/services/telephony/PstnIncomingCallNotifier.java
@@ -288,7 +288,11 @@
             }
         } else {
             TelecomManager tm = mPhone.getContext().getSystemService(TelecomManager.class);
-            tm.addNewIncomingCall(handle, extras);
+            if (connection.isMultiparty()) {
+                tm.addNewIncomingConference(handle, extras);
+            } else {
+                tm.addNewIncomingCall(handle, extras);
+            }
         }
     }
 
diff --git a/src/com/android/services/telephony/TelecomAccountRegistry.java b/src/com/android/services/telephony/TelecomAccountRegistry.java
index 5a1e6a6..69a00c5 100644
--- a/src/com/android/services/telephony/TelecomAccountRegistry.java
+++ b/src/com/android/services/telephony/TelecomAccountRegistry.java
@@ -49,6 +49,8 @@
 import android.telephony.TelephonyManager;
 import android.telephony.ims.ImsException;
 import android.telephony.ims.ImsMmTelManager;
+import android.telephony.ims.ImsReasonInfo;
+import android.telephony.ims.RegistrationManager;
 import android.telephony.ims.feature.MmTelFeature;
 import android.telephony.ims.stub.ImsRegistrationImplBase;
 import android.text.TextUtils;
@@ -86,9 +88,11 @@
         private final PstnPhoneCapabilitiesNotifier mPhoneCapabilitiesNotifier;
         private boolean mIsEmergency;
         private boolean mIsRttCapable;
+        private boolean mIsAdhocConfCapable;
         private boolean mIsEmergencyPreferred;
         private MmTelFeature.MmTelCapabilities mMmTelCapabilities;
         private ImsMmTelManager.CapabilityCallback mMmtelCapabilityCallback;
+        private RegistrationManager.RegistrationCallback mImsRegistrationCallback;
         private ImsMmTelManager mMmTelManager;
         private final boolean mIsDummy;
         private boolean mIsVideoCapable;
@@ -106,6 +110,7 @@
             mPhone = phone;
             mIsEmergency = isEmergency;
             mIsDummy = isDummy;
+            mIsAdhocConfCapable = mPhone.isImsRegistered();
             mAccount = registerPstnPhoneAccount(isEmergency, isDummy);
             Log.i(this, "Registered phoneAccount: %s with handle: %s",
                     mAccount, mAccount.getAccountHandle());
@@ -138,15 +143,38 @@
                     updateRttCapability();
                 }
             };
-
             registerMmTelCapabilityCallback();
+
+            mImsRegistrationCallback = new RegistrationManager.RegistrationCallback() {
+                @Override
+                public void onRegistered(int imsRadioTech) {
+                    updateAdhocConfCapability(true);
+                }
+
+                @Override
+                public void onRegistering(int imsRadioTech) {
+                    updateAdhocConfCapability(false);
+                }
+
+                @Override
+                public void onUnregistered(ImsReasonInfo imsReasonInfo) {
+                    updateAdhocConfCapability(false);
+                }
+            };
+            registerImsRegistrationCallback();
         }
 
         void teardown() {
             mIncomingCallNotifier.teardown();
             mPhoneCapabilitiesNotifier.teardown();
-            if (mMmTelManager != null && mMmtelCapabilityCallback != null) {
-                mMmTelManager.unregisterMmTelCapabilityCallback(mMmtelCapabilityCallback);
+            if (mMmTelManager != null) {
+                if (mMmtelCapabilityCallback != null) {
+                    mMmTelManager.unregisterMmTelCapabilityCallback(mMmtelCapabilityCallback);
+                }
+
+                if (mImsRegistrationCallback != null) {
+                    mMmTelManager.unregisterImsRegistrationCallback(mImsRegistrationCallback);
+                }
             }
         }
 
@@ -171,6 +199,25 @@
             }
         }
 
+        private void registerImsRegistrationCallback() {
+            if (mMmTelManager == null || mImsRegistrationCallback == null) {
+                return;
+            }
+
+            try {
+                mMmTelManager.registerImsRegistrationCallback(mContext.getMainExecutor(),
+                        mImsRegistrationCallback);
+            } catch (ImsException e) {
+                Log.w(this, "registerImsRegistrationCallback: registration failed, no ImsService"
+                        + " available. Exception: " + e.getMessage());
+                return;
+            } catch (IllegalArgumentException e) {
+                Log.w(this, "registerImsRegistrationCallback: registration failed, invalid"
+                        + " subscription, Exception" + e.getMessage());
+                return;
+            }
+        }
+
         /**
          * Trigger re-registration of this account.
          */
@@ -321,6 +368,12 @@
                 extras.putAll(getPhoneAccountExtras());
             }
 
+            if (mIsAdhocConfCapable && isCarrierAdhocConferenceCallSupported()) {
+                capabilities |= PhoneAccount.CAPABILITY_ADHOC_CONFERENCE_CALLING;
+            } else {
+                capabilities &= ~PhoneAccount.CAPABILITY_ADHOC_CONFERENCE_CALLING;
+            }
+
             final boolean isHandoverFromSupported = mContext.getResources().getBoolean(
                     R.bool.config_support_handover_from);
             if (isHandoverFromSupported && !isEmergency) {
@@ -511,6 +564,19 @@
         }
 
         /**
+         * Determines from carrier config whether adhoc conference calling is supported.
+         *
+         * @return {@code true} if adhoc conference calling is supported, {@code false} otherwise.
+         */
+        private boolean isCarrierAdhocConferenceCallSupported() {
+            PersistableBundle b =
+                    PhoneGlobals.getInstance().getCarrierConfigForSubId(mPhone.getSubId());
+            return b != null &&
+                    b.getBoolean(CarrierConfigManager.KEY_SUPPORT_ADHOC_CONFERENCE_CALLS_BOOL);
+        }
+
+
+        /**
          * Determines from carrier config whether merging calls is supported.
          *
          * @return {@code true} if merging calls is supported, {@code false} otherwise.
@@ -664,6 +730,26 @@
             }
         }
 
+        public void updateAdhocConfCapability(boolean isAdhocConfCapable) {
+            synchronized (mAccountsLock) {
+                if (!mAccounts.contains(this)) {
+                    // Account has already been torn down, don't try to register it again.
+                    // This handles the case where teardown has already happened, and we got a Ims
+                    // registartion update that lost the race for the mAccountsLock.  In such a
+                    // scenario by the time we get here, the original phone account could have been
+                    // torn down.
+                    return;
+                }
+
+                if (isAdhocConfCapable !=  mIsAdhocConfCapable) {
+                    Log.i(this, "updateAdhocConfCapability - changed, new value: "
+                            + isAdhocConfCapable);
+                    mIsAdhocConfCapable = isAdhocConfCapable;
+                    mAccount = registerPstnPhoneAccount(mIsEmergency, mIsDummy);
+                }
+            }
+        }
+
         public void updateRttCapability() {
             boolean isRttEnabled = isRttCurrentlySupported();
             if (isRttEnabled != mIsRttCapable) {
@@ -1048,6 +1134,21 @@
         return null;
     }
 
+    public void refreshAdhocConference(boolean isEnableAdhocConf) {
+        synchronized (mAccountsLock) {
+            Log.v(this, "refreshAdhocConference isEnable = " + isEnableAdhocConf);
+            for (AccountEntry entry : mAccounts) {
+                boolean hasAdhocConfCapability = entry.mAccount.hasCapabilities(
+                        PhoneAccount.CAPABILITY_ADHOC_CONFERENCE_CALLING);
+                if (!isEnableAdhocConf && hasAdhocConfCapability) {
+                    entry.updateAdhocConfCapability(isEnableAdhocConf);
+                } else if (isEnableAdhocConf && !hasAdhocConfCapability) {
+                    entry.updateAdhocConfCapability(entry.mPhone.isImsRegistered());
+                }
+            }
+        }
+    }
+
     /**
      * Returns whethere a the subscription associated with a {@link PhoneAccountHandle} is using a
      * sim call manager.
diff --git a/src/com/android/services/telephony/TelephonyConference.java b/src/com/android/services/telephony/TelephonyConference.java
index afbe89d..d720639 100644
--- a/src/com/android/services/telephony/TelephonyConference.java
+++ b/src/com/android/services/telephony/TelephonyConference.java
@@ -93,6 +93,16 @@
     }
 
     @Override
+    public void onAnswer(int videoState) {
+        Log.e(this, new Exception(), "Answer not supported for GSM conference call.");
+    }
+
+    @Override
+    public void onReject() {
+        Log.e(this, new Exception(), "Reject not supported for GSM conference call.");
+    }
+
+    @Override
     public void onMerge(Connection connection) {
         try {
             Phone phone = ((TelephonyConnection) connection).getPhone();
diff --git a/src/com/android/services/telephony/TelephonyConferenceBase.java b/src/com/android/services/telephony/TelephonyConferenceBase.java
index 5e7ecf6..1c81fb9 100644
--- a/src/com/android/services/telephony/TelephonyConferenceBase.java
+++ b/src/com/android/services/telephony/TelephonyConferenceBase.java
@@ -48,6 +48,14 @@
         public void onConferenceMembershipChanged(Connection connection) {}
 
         /**
+         * Listener called when there conference call state changes.
+         * @param conference The conference.
+         * @param oldState previous state of conference call.
+         * @param newState new state of conference call.
+         */
+        public void onStateChanged(Conference conference, int oldState, int newState) {}
+
+        /**
          * Listener called when a conference is destroyed.
          * @param conference The conference.
          */
@@ -129,6 +137,54 @@
     }
 
     /**
+     * Sets state to be on hold.
+     */
+     public final void setConferenceOnHold() {
+         int oldState = getState();
+         if (oldState == Connection.STATE_HOLDING) {
+             return;
+         }
+         setOnHold();
+         notifyStateChanged(oldState, getState());
+     }
+
+     /**
+      * Sets state to be dialing.
+      */
+     public final void setConferenceOnDialing() {
+         int oldState = getState();
+         if (oldState == Connection.STATE_DIALING) {
+             return;
+         }
+         setDialing();
+         notifyStateChanged(oldState, getState());
+     }
+
+     /**
+      * Sets state to be ringing.
+      */
+     public final void setConferenceOnRinging() {
+         int oldState = getState();
+         if (oldState == Connection.STATE_RINGING) {
+             return;
+         }
+         setRinging();
+         notifyStateChanged(oldState, getState());
+     }
+
+     /**
+      * Sets state to be active.
+      */
+     public final void setConferenceOnActive() {
+         int oldState = getState();
+         if (oldState == Connection.STATE_ACTIVE) {
+             return;
+         }
+         setActive();
+         notifyStateChanged(oldState, getState());
+     }
+
+    /**
      * Updates RIL voice radio technology used for current conference after its creation.
      */
     public void updateCallRadioTechAfterCreation() {
@@ -188,4 +244,12 @@
             listener.onDestroyed(this);
         }
     }
+
+    private void notifyStateChanged(int oldState, int newState) {
+        if (oldState != newState) {
+            for (TelephonyConferenceListener listener : mListeners) {
+                listener.onStateChanged(this, oldState, newState);
+            }
+        }
+    }
 }
diff --git a/src/com/android/services/telephony/TelephonyConnection.java b/src/com/android/services/telephony/TelephonyConnection.java
index 14f0cb8..edaf1de 100644
--- a/src/com/android/services/telephony/TelephonyConnection.java
+++ b/src/com/android/services/telephony/TelephonyConnection.java
@@ -114,6 +114,9 @@
     private static final int MSG_ON_CONNECTION_EVENT = 19;
     private static final int MSG_REDIAL_CONNECTION_CHANGED = 20;
 
+    private List<Uri> mParticipants;
+    private boolean mIsAdhocConferenceCall;
+
     private final Handler mHandler = new Handler(Looper.getMainLooper()) {
         @Override
         public void handleMessage(Message msg) {
@@ -163,7 +166,9 @@
                                 "not foreground connection, skipping");
                         return;
                     }
-                    setRingbackRequested((Boolean) ((AsyncResult) msg.obj).result);
+                    boolean ringback = (Boolean) ((AsyncResult) msg.obj).result;
+                    setRingbackRequested(ringback);
+                    notifyRingbackRequested(ringback);
                     break;
                 case MSG_DISCONNECT:
                     updateState();
@@ -463,6 +468,7 @@
         public void onVideoProviderChanged(android.telecom.Connection c,
                 Connection.VideoProvider videoProvider) {}
         public void onVideoStateChanged(android.telecom.Connection c, int videoState) {}
+        public void onRingbackRequested(Connection c, boolean ringback) {}
     }
 
     private final PostDialListener mPostDialListener = new PostDialListener() {
@@ -876,14 +882,7 @@
 
     @Override
     public void onAnswer(int videoState) {
-        Log.v(this, "onAnswer");
-        if (isValidRingingCall() && getPhone() != null) {
-            try {
-                getPhone().acceptCall(videoState);
-            } catch (CallStateException e) {
-                Log.e(this, e, "Failed to accept call.");
-            }
-        }
+        performAnswer(videoState);
     }
 
     @Override
@@ -927,7 +926,11 @@
 
     @Override
     public void onReject() {
-        Log.v(this, "onReject");
+        performReject();
+    }
+
+    public void performReject() {
+        Log.v(this, "performReject");
         if (isValidRingingCall()) {
             mHandler.obtainMessage(MSG_HANGUP, android.telephony.DisconnectCause.INCOMING_REJECTED)
                     .sendToTarget();
@@ -1001,6 +1004,17 @@
         originalConnection.sendRttModifyResponse(textStream);
     }
 
+    public void performAnswer(int videoState) {
+        Log.v(this, "performAnswer");
+        if (isValidRingingCall() && getPhone() != null) {
+            try {
+                getPhone().acceptCall(videoState);
+            } catch (CallStateException e) {
+                Log.e(this, e, "Failed to accept call.");
+            }
+        }
+    }
+
     public void performHold() {
         Log.v(this, "performHold");
         // TODO: Can dialing calls be put on hold as well since they take up the
@@ -1167,6 +1181,8 @@
         newProperties = changeBitmask(newProperties, PROPERTY_IS_RTT, isRtt());
         newProperties = changeBitmask(newProperties, PROPERTY_NETWORK_IDENTIFIED_EMERGENCY_CALL,
                 isNetworkIdentifiedEmergencyCall());
+        newProperties = changeBitmask(newProperties, PROPERTY_IS_ADHOC_CONFERENCE,
+                isAdhocConferenceCall());
 
         if (getConnectionProperties() != newProperties) {
             setTelephonyConnectionProperties(newProperties);
@@ -1255,6 +1271,7 @@
         setTelephonyVideoState(mOriginalConnection.getVideoState());
         setOriginalConnectionCapabilities(mOriginalConnection.getConnectionCapabilities());
         setIsNetworkIdentifiedEmergencyCall(mOriginalConnection.isNetworkIdentifiedEmergencyCall());
+        setIsAdhocConferenceCall(mOriginalConnection.isAdhocConference());
         setAudioModeIsVoip(mOriginalConnection.getAudioModeIsVoip());
         setTelephonyVideoProvider(mOriginalConnection.getVideoProvider());
         setAudioQuality(mOriginalConnection.getAudioQuality());
@@ -1511,6 +1528,39 @@
         return true;
     }
 
+    /**
+     * @return The address's to which this Connection is currently communicating.
+     */
+    public final @Nullable List<Uri> getParticipants() {
+        return mParticipants;
+    }
+
+    /**
+     * Sets the value of the {@link #getParticipants()} property.
+     *
+     * @param address The participant address's.
+     */
+    public final void setParticipants(@Nullable List<Uri> address) {
+        mParticipants = address;
+    }
+
+    /**
+     * @return true if connection is adhocConference call else false.
+     */
+    public final boolean isAdhocConferenceCall() {
+        return mIsAdhocConferenceCall;
+    }
+
+    /**
+     * Sets the value of the {@link #isAdhocConferenceCall()} property.
+     *
+     * @param isAdhocConferenceCall represents if the call is adhoc conference call or not.
+     */
+    public void setIsAdhocConferenceCall(boolean isAdhocConferenceCall) {
+        mIsAdhocConferenceCall = isAdhocConferenceCall;
+        updateConnectionProperties();
+    }
+
     private boolean canHoldImsCalls() {
         PersistableBundle b = getCarrierConfig();
         // Return true if the CarrierConfig is unavailable
@@ -2530,6 +2580,8 @@
         }
         sb.append(" confSupported:");
         sb.append(mIsConferenceSupported ? "Y" : "N");
+        sb.append(" isAdhocConf:");
+        sb.append(isAdhocConferenceCall() ? "Y" : "N");
         sb.append("]");
         return sb.toString();
     }
@@ -2855,6 +2907,16 @@
     }
 
     /**
+     * Notifies {@link TelephonyConnectionListener}s of a whether to play Ringback Tone or not.
+     * @param ringback Whether the ringback tone is to be played
+     */
+    private void notifyRingbackRequested(boolean ringback) {
+        for (TelephonyConnectionListener listener : mTelephonyListeners) {
+            listener.onRingbackRequested(this, ringback);
+        }
+    }
+
+    /**
      * Notifies {@link TelephonyConnectionListener}s of changes to the video provider for a
      * connection.
      * @param videoProvider The new video provider.
diff --git a/src/com/android/services/telephony/TelephonyConnectionService.java b/src/com/android/services/telephony/TelephonyConnectionService.java
index 40b941e..2178537 100644
--- a/src/com/android/services/telephony/TelephonyConnectionService.java
+++ b/src/com/android/services/telephony/TelephonyConnectionService.java
@@ -516,6 +516,136 @@
         return super.onUnbind(intent);
     }
 
+    private Conference placeOutgoingConference(ConnectionRequest request,
+            Connection resultConnection, Phone phone) {
+        if (resultConnection instanceof TelephonyConnection) {
+            return placeOutgoingConference((TelephonyConnection) resultConnection, phone, request);
+        }
+        return null;
+    }
+
+    private Conference placeOutgoingConference(TelephonyConnection conferenceHostConnection,
+            Phone phone, ConnectionRequest request) {
+        updatePhoneAccount(conferenceHostConnection, phone);
+        com.android.internal.telephony.Connection originalConnection = null;
+        try {
+            originalConnection = phone.startConference(
+                    getParticipantsToDial(request.getParticipants()),
+                    new ImsPhone.ImsDialArgs.Builder()
+                    .setVideoState(request.getVideoState())
+                    .setRttTextStream(conferenceHostConnection.getRttTextStream())
+                    .build());
+        } catch (CallStateException e) {
+            Log.e(this, e, "placeOutgoingConference, phone.startConference exception: " + e);
+            handleCallStateException(e, conferenceHostConnection, phone);
+            return null;
+        }
+
+        if (originalConnection == null) {
+            Log.d(this, "placeOutgoingConference, phone.startConference returned null");
+            conferenceHostConnection.setDisconnected(DisconnectCauseUtil.toTelecomDisconnectCause(
+                    android.telephony.DisconnectCause.OUTGOING_FAILURE,
+                    "conferenceHostConnection is null",
+                    phone.getPhoneId()));
+            conferenceHostConnection.clearOriginalConnection();
+            conferenceHostConnection.destroy();
+        } else {
+            conferenceHostConnection.setOriginalConnection(originalConnection);
+        }
+
+        return prepareConference(conferenceHostConnection, request.getAccountHandle());
+    }
+
+    Conference prepareConference(Connection conn, PhoneAccountHandle phoneAccountHandle) {
+        if (!(conn instanceof TelephonyConnection)) {
+            Log.w(this, "prepareConference returning NULL conference");
+            return null;
+        }
+
+        TelephonyConnection connection = (TelephonyConnection)conn;
+        ImsConference conference = new ImsConference(TelecomAccountRegistry.getInstance(this),
+                mTelephonyConnectionServiceProxy, connection,
+                phoneAccountHandle, () -> true);
+        mImsConferenceController.addConference(conference);
+        conference.setVideoState(connection,
+                connection.getVideoState());
+        conference.setVideoProvider(connection,
+                connection.getVideoProvider());
+        conference.setStatusHints(connection.getStatusHints());
+        conference.setAddress(connection.getAddress(),
+                connection.getAddressPresentation());
+        conference.setCallerDisplayName(connection.getCallerDisplayName(),
+                connection.getCallerDisplayNamePresentation());
+        conference.setParticipants(connection.getParticipants());
+        return conference;
+    }
+
+    @Override
+    public @Nullable Conference onCreateIncomingConference(
+            @Nullable PhoneAccountHandle connectionManagerPhoneAccount,
+            @NonNull final ConnectionRequest request) {
+        Log.i(this, "onCreateIncomingConference, request: " + request);
+        Connection connection = onCreateIncomingConnection(connectionManagerPhoneAccount, request);
+        Log.d(this, "onCreateIncomingConference, connection: %s", connection);
+        if (connection == null) {
+            Log.i(this, "onCreateIncomingConference, implementation returned null connection.");
+            return Conference.createFailedConference(
+                    new DisconnectCause(DisconnectCause.ERROR, "IMPL_RETURNED_NULL_CONNECTION"),
+                    request.getAccountHandle());
+        }
+
+        final Phone phone = getPhoneForAccount(request.getAccountHandle(),
+                false /* isEmergencyCall*/, null /* not an emergency call */);
+        if (phone == null) {
+            Log.d(this, "onCreateIncomingConference, phone is null");
+            return Conference.createFailedConference(
+                    DisconnectCauseUtil.toTelecomDisconnectCause(
+                            android.telephony.DisconnectCause.OUT_OF_SERVICE,
+                            "Phone is null"),
+                    request.getAccountHandle());
+        }
+
+        return prepareConference(connection, request.getAccountHandle());
+    }
+
+    @Override
+    public @Nullable Conference onCreateOutgoingConference(
+            @Nullable PhoneAccountHandle connectionManagerPhoneAccount,
+            @NonNull final ConnectionRequest request) {
+        Log.i(this, "onCreateOutgoingConference, request: " + request);
+        Connection connection = onCreateOutgoingConnection(connectionManagerPhoneAccount, request);
+        Log.d(this, "onCreateOutgoingConference, connection: %s", connection);
+        if (connection == null) {
+            Log.i(this, "onCreateOutgoingConference, implementation returned null connection.");
+            return Conference.createFailedConference(
+                    new DisconnectCause(DisconnectCause.ERROR, "IMPL_RETURNED_NULL_CONNECTION"),
+                    request.getAccountHandle());
+        }
+
+        final Phone phone = getPhoneForAccount(request.getAccountHandle(),
+                false /* isEmergencyCall*/, null /* not an emergency call */);
+        if (phone == null) {
+            Log.d(this, "onCreateOutgoingConference, phone is null");
+            return Conference.createFailedConference(
+                    DisconnectCauseUtil.toTelecomDisconnectCause(
+                            android.telephony.DisconnectCause.OUT_OF_SERVICE,
+                            "Phone is null"),
+                    request.getAccountHandle());
+        }
+
+        return placeOutgoingConference(request, connection, phone);
+    }
+
+    private String[] getParticipantsToDial(List<Uri> participants) {
+        String[] participantsToDial = new String[participants.size()];
+        int i = 0;
+        for (Uri participant : participants) {
+           participantsToDial[i] = participant.getSchemeSpecificPart();
+           i++;
+        }
+        return participantsToDial;
+    }
+
     @Override
     public Connection onCreateOutgoingConnection(
             PhoneAccountHandle connectionManagerPhoneAccount,
@@ -523,7 +653,9 @@
         Log.i(this, "onCreateOutgoingConnection, request: " + request);
 
         Uri handle = request.getAddress();
-        if (handle == null) {
+        boolean isAdhocConference = request.isAdhocConferenceCall();
+
+        if (!isAdhocConference && handle == null) {
             Log.d(this, "onCreateOutgoingConnection, handle is null");
             return Connection.createFailedConnection(
                     mDisconnectCauseFactory.toTelecomDisconnectCause(
@@ -626,7 +758,6 @@
         }
         final String numberToDial = number;
 
-
         final boolean isAirplaneModeOn = mDeviceState.isAirplaneModeOn(this);
 
         boolean needToTurnOnRadio = (isEmergencyNumber && (!isRadioOn() || isAirplaneModeOn))
@@ -698,7 +829,15 @@
             if (!isEmergencyNumber) {
                 final Connection resultConnection = getTelephonyConnection(request, numberToDial,
                         false, handle, phone);
-                return placeOutgoingConnection(request, resultConnection, phone);
+                if (isAdhocConference) {
+                    if (resultConnection instanceof TelephonyConnection) {
+                        TelephonyConnection conn = (TelephonyConnection)resultConnection;
+                        conn.setParticipants(request.getParticipants());
+                    }
+                    return resultConnection;
+                } else {
+                    return placeOutgoingConnection(request, resultConnection, phone);
+                }
             } else {
                 final Connection resultConnection = getTelephonyConnection(request, numberToDial,
                         true, handle, phone);
@@ -981,7 +1120,7 @@
 
         final TelephonyConnection connection =
                 createConnectionFor(phone, null, true /* isOutgoing */, request.getAccountHandle(),
-                        request.getTelecomCallId());
+                        request.getTelecomCallId(), request.isAdhocConferenceCall());
         if (connection == null) {
             return Connection.createFailedConnection(
                     mDisconnectCauseFactory.toTelecomDisconnectCause(
@@ -994,6 +1133,8 @@
         connection.setTelephonyVideoState(request.getVideoState());
         connection.setRttTextStream(request.getRttTextStream());
         connection.setTtyEnabled(isTtyModeEnabled);
+        connection.setIsAdhocConferenceCall(request.isAdhocConferenceCall());
+        connection.setParticipants(request.getParticipants());
         return connection;
     }
 
@@ -1042,7 +1183,8 @@
 
         TelephonyConnection connection =
                 createConnectionFor(phone, originalConnection, false /* isOutgoing */,
-                        request.getAccountHandle(), request.getTelecomCallId());
+                        request.getAccountHandle(), request.getTelecomCallId(),
+                        request.isAdhocConferenceCall());
         handleIncomingRtt(request, originalConnection);
         if (connection == null) {
             return Connection.createCanceledConnection();
@@ -1154,6 +1296,29 @@
         connection.close();
     }
 
+    /**
+     * Called by the {@link ConnectionService} when a newly created {@link Conference} has been
+     * added to the {@link ConnectionService} and sent to Telecom.  Here it is safe to send
+     * connection events.
+     *
+     * @param conference the {@link Conference}.
+     */
+    @Override
+    public void onCreateConferenceComplete(Conference conference) {
+        if (conference instanceof ImsConference) {
+            ImsConference imsConference = (ImsConference)conference;
+            TelephonyConnection telephonyConnection =
+                    (TelephonyConnection)(imsConference.getConferenceHost());
+            maybeSendInternationalCallEvent(telephonyConnection);
+        }
+    }
+
+    public void onCreateIncomingConferenceFailed(PhoneAccountHandle connectionManagerPhoneAccount,
+            ConnectionRequest request) {
+        Log.i(this, "onCreateIncomingConferenceFailed, request: " + request);
+        onCreateIncomingConnectionFailed(connectionManagerPhoneAccount, request);
+    }
+
     @Override
     public void triggerConferenceRecalculate() {
         if (mTelephonyConferenceController.shouldRecalculate()) {
@@ -1495,34 +1660,7 @@
             }
         } catch (CallStateException e) {
             Log.e(this, e, "placeOutgoingConnection, phone.dial exception: " + e);
-            int cause = android.telephony.DisconnectCause.OUTGOING_FAILURE;
-            switch (e.getError()) {
-                case CallStateException.ERROR_OUT_OF_SERVICE:
-                    cause = android.telephony.DisconnectCause.OUT_OF_SERVICE;
-                    break;
-                case CallStateException.ERROR_POWER_OFF:
-                    cause = android.telephony.DisconnectCause.POWER_OFF;
-                    break;
-                case CallStateException.ERROR_ALREADY_DIALING:
-                    cause = android.telephony.DisconnectCause.ALREADY_DIALING;
-                    break;
-                case CallStateException.ERROR_CALL_RINGING:
-                    cause = android.telephony.DisconnectCause.CANT_CALL_WHILE_RINGING;
-                    break;
-                case CallStateException.ERROR_CALLING_DISABLED:
-                    cause = android.telephony.DisconnectCause.CALLING_DISABLED;
-                    break;
-                case CallStateException.ERROR_TOO_MANY_CALLS:
-                    cause = android.telephony.DisconnectCause.TOO_MANY_ONGOING_CALLS;
-                    break;
-                case CallStateException.ERROR_OTASP_PROVISIONING_IN_PROCESS:
-                    cause = android.telephony.DisconnectCause.OTASP_PROVISIONING_IN_PROCESS;
-                    break;
-            }
-            connection.setTelephonyConnectionDisconnected(
-                    mDisconnectCauseFactory.toTelecomDisconnectCause(cause, e.getMessage(),
-                            phone.getPhoneId()));
-            connection.close();
+            handleCallStateException(e, connection, phone);
             return;
         }
 
@@ -1576,12 +1714,55 @@
                 CarrierConfigManager.KEY_ALLOW_HOLD_CALL_DURING_EMERGENCY_BOOL, true);
     }
 
+    private void handleCallStateException(CallStateException e, TelephonyConnection connection,
+            Phone phone) {
+        int cause = android.telephony.DisconnectCause.OUTGOING_FAILURE;
+        switch (e.getError()) {
+            case CallStateException.ERROR_OUT_OF_SERVICE:
+                cause = android.telephony.DisconnectCause.OUT_OF_SERVICE;
+                break;
+            case CallStateException.ERROR_POWER_OFF:
+                 cause = android.telephony.DisconnectCause.POWER_OFF;
+                 break;
+            case CallStateException.ERROR_ALREADY_DIALING:
+                 cause = android.telephony.DisconnectCause.ALREADY_DIALING;
+                 break;
+            case CallStateException.ERROR_CALL_RINGING:
+                 cause = android.telephony.DisconnectCause.CANT_CALL_WHILE_RINGING;
+                 break;
+            case CallStateException.ERROR_CALLING_DISABLED:
+                 cause = android.telephony.DisconnectCause.CALLING_DISABLED;
+                 break;
+            case CallStateException.ERROR_TOO_MANY_CALLS:
+                 cause = android.telephony.DisconnectCause.TOO_MANY_ONGOING_CALLS;
+                 break;
+            case CallStateException.ERROR_OTASP_PROVISIONING_IN_PROCESS:
+                 cause = android.telephony.DisconnectCause.OTASP_PROVISIONING_IN_PROCESS;
+                 break;
+        }
+        connection.setTelephonyConnectionDisconnected(
+                DisconnectCauseUtil.toTelecomDisconnectCause(cause, e.getMessage(),
+                        phone.getPhoneId()));
+        connection.close();
+    }
+
     private TelephonyConnection createConnectionFor(
             Phone phone,
             com.android.internal.telephony.Connection originalConnection,
             boolean isOutgoing,
             PhoneAccountHandle phoneAccountHandle,
             String telecomCallId) {
+            return createConnectionFor(phone, originalConnection, isOutgoing, phoneAccountHandle,
+                    telecomCallId, false);
+    }
+
+    private TelephonyConnection createConnectionFor(
+            Phone phone,
+            com.android.internal.telephony.Connection originalConnection,
+            boolean isOutgoing,
+            PhoneAccountHandle phoneAccountHandle,
+            String telecomCallId,
+            boolean isAdhocConference) {
         TelephonyConnection returnConnection = null;
         int phoneType = phone.getPhoneType();
         if (phoneType == TelephonyManager.PHONE_TYPE_GSM) {
@@ -1592,8 +1773,10 @@
                     allowsMute, isOutgoing, telecomCallId);
         }
         if (returnConnection != null) {
-            // Listen to Telephony specific callbacks from the connection
-            returnConnection.addTelephonyConnectionListener(mTelephonyConnectionListener);
+            if (!isAdhocConference) {
+                // Listen to Telephony specific callbacks from the connection
+                returnConnection.addTelephonyConnectionListener(mTelephonyConnectionListener);
+            } 
             returnConnection.setVideoPauseSupported(
                     TelecomAccountRegistry.getInstance(this).isVideoPauseSupported(
                             phoneAccountHandle));