diff --git a/telecomm/java/android/telecom/Call.java b/telecomm/java/android/telecom/Call.java
index c69b7c2..d67a0d6 100644
--- a/telecomm/java/android/telecom/Call.java
+++ b/telecomm/java/android/telecom/Call.java
@@ -16,12 +16,21 @@
 
 package android.telecom;
 
+import android.annotation.IntDef;
+import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.Handler;
+import android.os.ParcelFileDescriptor;
 
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
 import java.lang.String;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -828,6 +837,142 @@
          * @param extras Extras associated with the connection event.
          */
         public void onConnectionEvent(Call call, String event, Bundle extras) {}
+
+        /**
+         * Invoked when the RTT mode changes for this call.
+         * @param call The call whose RTT mode has changed.
+         * @param mode the new RTT mode, one of
+         * {@link RttCall#RTT_MODE_FULL}, {@link RttCall#RTT_MODE_HCO},
+         *             or {@link RttCall#RTT_MODE_VCO}
+         */
+        public void onRttModeChanged(Call call, int mode) {}
+
+        /**
+         * Invoked when the call's RTT status changes, either from off to on or from on to off.
+         * @param call The call whose RTT status has changed.
+         * @param enabled whether RTT is now enabled or disabled
+         * @param rttCall the {@link RttCall} object to use for reading and writing if RTT is now
+         *                on, null otherwise.
+         */
+        public void onRttStatusChanged(Call call, boolean enabled, RttCall rttCall) {}
+
+        /**
+         * Invoked when the remote end of the connection has requested that an RTT communication
+         * channel be opened. A response to this should be sent via {@link #respondToRttRequest}
+         * with the same ID that this method is invoked with.
+         * @param call The call which the RTT request was placed on
+         * @param id The ID of the request.
+         */
+        public void onRttRequest(Call call, int id) {}
+    }
+
+    /**
+     * A class that holds the state that describes the state of the RTT channel to the remote
+     * party, if it is active.
+     */
+    public static final class RttCall {
+        @Retention(RetentionPolicy.SOURCE)
+        @IntDef({RTT_MODE_INVALID, RTT_MODE_FULL, RTT_MODE_HCO, RTT_MODE_VCO})
+        public @interface RttAudioMode {}
+
+        /**
+         * For metrics use. Default value in the proto.
+         * @hide
+         */
+        public static final int RTT_MODE_INVALID = 0;
+
+        /**
+         * Indicates that there should be a bidirectional audio stream between the two parties
+         * on the call.
+         */
+        public static final int RTT_MODE_FULL = 1;
+
+        /**
+         * Indicates that the local user should be able to hear the audio stream from the remote
+         * user, but not vice versa. Equivalent to muting the microphone.
+         */
+        public static final int RTT_MODE_HCO = 2;
+
+        /**
+         * Indicates that the remote user should be able to hear the audio stream from the local
+         * user, but not vice versa. Equivalent to setting the volume to zero.
+         */
+        public static final int RTT_MODE_VCO = 3;
+
+        private static final int READ_BUFFER_SIZE = 1000;
+
+        private InputStreamReader mReceiveStream;
+        private OutputStreamWriter mTransmitStream;
+        private int mRttMode;
+        private final InCallAdapter mInCallAdapter;
+        private char[] mReadBuffer = new char[READ_BUFFER_SIZE];
+
+        /**
+         * @hide
+         */
+        public RttCall(InputStreamReader receiveStream, OutputStreamWriter transmitStream,
+                int mode, InCallAdapter inCallAdapter) {
+            mReceiveStream = receiveStream;
+            mTransmitStream = transmitStream;
+            mRttMode = mode;
+            mInCallAdapter = inCallAdapter;
+        }
+
+        /**
+         * Returns the current RTT audio mode.
+         * @return Current RTT audio mode. One of {@link #RTT_MODE_FULL}, {@link #RTT_MODE_VCO}, or
+         * {@link #RTT_MODE_HCO}.
+         */
+        public int getRttAudioMode() {
+            return mRttMode;
+        }
+
+        /**
+         * Sets the RTT audio mode. The requested mode change will be communicated through
+         * {@link Callback#onRttModeChanged(Call, int)}.
+         * @param mode The desired RTT audio mode, one of {@link #RTT_MODE_FULL},
+         * {@link #RTT_MODE_VCO}, or {@link #RTT_MODE_HCO}.
+         */
+        public void setRttMode(@RttAudioMode int mode) {
+            mInCallAdapter.setRttMode(mode);
+        }
+
+        /**
+         * Writes the string {@param input} into the outgoing text stream for this RTT call. Since
+         * RTT transmits text in real-time, this method should be called once for each character
+         * the user enters into the device.
+         *
+         * This method is not thread-safe -- calling it from multiple threads simultaneously may
+         * lead to interleaved text.
+         * @param input The message to send to the remote user.
+         */
+        public void write(String input) throws IOException {
+            mTransmitStream.write(input);
+            mTransmitStream.flush();
+        }
+
+        /**
+         * Reads a string from the remote user, blocking if there is no data available. Returns
+         * {@code null} if the RTT conversation has been terminated and there is no further data
+         * to read.
+         *
+         * This method is not thread-safe -- calling it from multiple threads simultaneously may
+         * lead to interleaved text.
+         * @return A string containing text sent by the remote user, or {@code null} if the
+         * conversation has been terminated or if there was an error while reading.
+         */
+        public String read() {
+            try {
+                int numRead = mReceiveStream.read(mReadBuffer, 0, READ_BUFFER_SIZE);
+                if (numRead < 0) {
+                    return null;
+                }
+                return new String(mReadBuffer, 0, numRead);
+            } catch (IOException e) {
+                Log.w(this, "Exception encountered when reading from InputStreamReader: %s", e);
+                return null;
+            }
+        }
     }
 
     /**
@@ -856,6 +1001,7 @@
     private String mCallingPackage;
     private String mRemainingPostDialSequence;
     private VideoCallImpl mVideoCallImpl;
+    private RttCall mRttCall;
     private Details mDetails;
     private Bundle mExtras;
 
@@ -1054,6 +1200,34 @@
     }
 
     /**
+     * Sends an RTT upgrade request to the remote end of the connection. Success is not
+     * guaranteed, and notification of success will be via the
+     * {@link Callback#onRttStatusChanged(Call, boolean, RttCall)} callback.
+     */
+    public void sendRttRequest() {
+        mInCallAdapter.sendRttRequest();
+    }
+
+    /**
+     * Responds to an RTT request received via the {@link Callback#onRttRequest(Call, int)} )}
+     * callback.
+     * The ID used here should be the same as the ID that was received via the callback.
+     * @param id The request ID received via {@link Callback#onRttRequest(Call, int)}
+     * @param accept {@code true} if the RTT request should be accepted, {@code false} otherwise.
+     */
+    public void respondToRttRequest(int id, boolean accept) {
+        mInCallAdapter.respondToRttRequest(id, accept);
+    }
+
+    /**
+     * Terminate the RTT session on this call. The resulting state change will be notified via
+     * the {@link Callback#onRttStatusChanged(Call, boolean, RttCall)} callback.
+     */
+    public void stopRtt() {
+        mInCallAdapter.stopRtt();
+    }
+
+    /**
      * Adds some extras to this {@link Call}.  Existing keys are replaced and new ones are
      * added.
      * <p>
@@ -1233,6 +1407,23 @@
     }
 
     /**
+     * Returns this call's RttCall object. The {@link RttCall} instance is used to send and
+     * receive RTT text data, as well as to change the RTT mode.
+     * @return A {@link Call.RttCall}. {@code null} if there is no active RTT connection.
+     */
+    public @Nullable RttCall getRttCall() {
+        return mRttCall;
+    }
+
+    /**
+     * Returns whether this call has an active RTT connection.
+     * @return true if there is a connection, false otherwise.
+     */
+    public boolean isRttActive() {
+        return mRttCall != null;
+    }
+
+    /**
      * Registers a callback to this {@code Call}.
      *
      * @param callback A {@code Callback}.
@@ -1426,6 +1617,32 @@
             fireConferenceableCallsChanged();
         }
 
+        boolean isRttChanged = false;
+        boolean rttModeChanged = false;
+        if (parcelableCall.getParcelableRttCall() != null && parcelableCall.getIsRttCallChanged()) {
+            ParcelableRttCall parcelableRttCall = parcelableCall.getParcelableRttCall();
+            InputStreamReader receiveStream = new InputStreamReader(
+                    new ParcelFileDescriptor.AutoCloseInputStream(
+                            parcelableRttCall.getReceiveStream()),
+                    StandardCharsets.UTF_8);
+            OutputStreamWriter transmitStream = new OutputStreamWriter(
+                    new ParcelFileDescriptor.AutoCloseOutputStream(
+                            parcelableRttCall.getTransmitStream()),
+                    StandardCharsets.UTF_8);
+            RttCall newRttCall = new Call.RttCall(
+                    receiveStream, transmitStream, parcelableRttCall.getRttMode(), mInCallAdapter);
+            if (mRttCall == null) {
+                isRttChanged = true;
+            } else if (mRttCall.getRttAudioMode() != newRttCall.getRttAudioMode()) {
+                rttModeChanged = true;
+            }
+            mRttCall = newRttCall;
+        } else if (mRttCall != null && parcelableCall.getParcelableRttCall() == null
+                && parcelableCall.getIsRttCallChanged()) {
+            isRttChanged = true;
+            mRttCall = null;
+        }
+
         // Now we fire updates, ensuring that any client who listens to any of these notifications
         // gets the most up-to-date state.
 
@@ -1447,6 +1664,12 @@
         if (childrenChanged) {
             fireChildrenChanged(getChildren());
         }
+        if (isRttChanged) {
+            fireOnIsRttChanged(mRttCall != null, mRttCall);
+        }
+        if (rttModeChanged) {
+            fireOnRttModeChanged(mRttCall.getRttAudioMode());
+        }
 
         // If we have transitioned to DISCONNECTED, that means we need to notify clients and
         // remove ourselves from the Phone. Note that we do this after completing all state updates
@@ -1477,6 +1700,15 @@
         fireOnConnectionEvent(event, extras);
     }
 
+    /** {@hide} */
+    final void internalOnRttUpgradeRequest(final int requestId) {
+        for (CallbackRecord<Callback> record : mCallbackRecords) {
+            final Call call = this;
+            final Callback callback = record.getCallback();
+            record.getHandler().post(() -> callback.onRttRequest(call, requestId));
+        }
+    }
+
     private void fireStateChanged(final int newState) {
         for (CallbackRecord<Callback> record : mCallbackRecords) {
             final Call call = this;
@@ -1645,6 +1877,32 @@
     }
 
     /**
+     * Notifies listeners of an RTT on/off change
+     *
+     * @param enabled True if RTT is now enabled, false otherwise
+     */
+    private void fireOnIsRttChanged(final boolean enabled, final RttCall rttCall) {
+        for (CallbackRecord<Callback> record : mCallbackRecords) {
+            final Call call = this;
+            final Callback callback = record.getCallback();
+            record.getHandler().post(() -> callback.onRttStatusChanged(call, enabled, rttCall));
+        }
+    }
+
+    /**
+     * Notifies listeners of a RTT mode change
+     *
+     * @param mode The new RTT mode
+     */
+    private void fireOnRttModeChanged(final int mode) {
+        for (CallbackRecord<Callback> record : mCallbackRecords) {
+            final Call call = this;
+            final Callback callback = record.getCallback();
+            record.getHandler().post(() -> callback.onRttModeChanged(call, mode));
+        }
+    }
+
+    /**
      * Determines if two bundles are equal.
      *
      * @param bundle The original bundle.
diff --git a/telecomm/java/android/telecom/Connection.java b/telecomm/java/android/telecom/Connection.java
index b7391b4..3e690b9 100644
--- a/telecomm/java/android/telecom/Connection.java
+++ b/telecomm/java/android/telecom/Connection.java
@@ -31,10 +31,14 @@
 import android.os.IBinder;
 import android.os.Looper;
 import android.os.Message;
+import android.os.ParcelFileDescriptor;
 import android.os.RemoteException;
 import android.util.ArraySet;
 import android.view.Surface;
 
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -385,8 +389,14 @@
      */
     public static final int PROPERTY_SELF_MANAGED = 1<<7;
 
+    /**
+     * When set, indicates that a connection has an active RTT session associated with it.
+     * @hide
+     */
+    public static final int PROPERTY_IS_RTT = 1 << 8;
+
     //**********************************************************************************************
-    // Next PROPERTY value: 1<<8
+    // Next PROPERTY value: 1<<9
     //**********************************************************************************************
 
     /**
@@ -757,6 +767,65 @@
     }
 
     /**
+     * Provides methods to read and write RTT data to/from the in-call app.
+     * @hide
+     */
+    public static final class RttTextStream {
+        private static final int READ_BUFFER_SIZE = 1000;
+        private final InputStreamReader mPipeFromInCall;
+        private final OutputStreamWriter mPipeToInCall;
+        private char[] mReadBuffer = new char[READ_BUFFER_SIZE];
+
+        /**
+         * @hide
+         */
+        public RttTextStream(ParcelFileDescriptor toInCall, ParcelFileDescriptor fromInCall) {
+            mPipeFromInCall = new InputStreamReader(
+                    new ParcelFileDescriptor.AutoCloseInputStream(fromInCall));
+            mPipeToInCall = new OutputStreamWriter(
+                    new ParcelFileDescriptor.AutoCloseOutputStream(toInCall));
+        }
+
+        /**
+         * Writes the string {@param input} into the text stream to the UI for this RTT call. Since
+         * RTT transmits text in real-time, this method should be called as often as text snippets
+         * are received from the remote user, even if it is only one character.
+         *
+         * This method is not thread-safe -- calling it from multiple threads simultaneously may
+         * lead to interleaved text.
+         * @param input The message to send to the in-call app.
+         */
+        public void write(String input) throws IOException {
+            mPipeToInCall.write(input);
+            mPipeToInCall.flush();
+        }
+
+
+        /**
+         * Reads a string from the in-call app, blocking if there is no data available. Returns
+         * {@code null} if the RTT conversation has been terminated and there is no further data
+         * to read.
+         *
+         * This method is not thread-safe -- calling it from multiple threads simultaneously may
+         * lead to interleaved text.
+         * @return A string containing text entered by the user, or {@code null} if the
+         * conversation has been terminated or if there was an error while reading.
+         */
+        public String read() {
+            try {
+                int numRead = mPipeFromInCall.read(mReadBuffer, 0, READ_BUFFER_SIZE);
+                if (numRead < 0) {
+                    return null;
+                }
+                return new String(mReadBuffer, 0, numRead);
+            } catch (IOException e) {
+                Log.w(this, "Exception encountered when reading from InputStreamReader: %s", e);
+                return null;
+            }
+        }
+    }
+
+    /**
      * Provides a means of controlling the video session associated with a {@link Connection}.
      * <p>
      * Implementations create a custom subclass of {@link VideoProvider} and the
diff --git a/telecomm/java/android/telecom/ConnectionRequest.java b/telecomm/java/android/telecom/ConnectionRequest.java
index 2343462..054de4c 100644
--- a/telecomm/java/android/telecom/ConnectionRequest.java
+++ b/telecomm/java/android/telecom/ConnectionRequest.java
@@ -19,6 +19,7 @@
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.Parcel;
+import android.os.ParcelFileDescriptor;
 import android.os.Parcelable;
 
 /**
@@ -27,13 +28,121 @@
  */
 public final class ConnectionRequest implements Parcelable {
 
-    // TODO: Token to limit recursive invocations
+    /**
+     * Builder class for {@link ConnectionRequest}
+     * @hide
+     */
+    public static final class Builder {
+        private PhoneAccountHandle mAccountHandle;
+        private Uri mAddress;
+        private Bundle mExtras;
+        private int mVideoState = VideoProfile.STATE_AUDIO_ONLY;
+        private String mTelecomCallId;
+        private boolean mShouldShowIncomingCallUi = false;
+        private ParcelFileDescriptor mRttPipeToInCall;
+        private ParcelFileDescriptor mRttPipeFromInCall;
+
+        public Builder() { }
+
+        /**
+         * Sets the phone account handle for the resulting {@link ConnectionRequest}
+         * @param accountHandle The accountHandle which should be used to place the call.
+         */
+        public Builder setAccountHandle(PhoneAccountHandle accountHandle) {
+            this.mAccountHandle = accountHandle;
+            return this;
+        }
+
+        /**
+         * Sets the address for the resulting {@link ConnectionRequest}
+         * @param address The address(e.g., phone number) to which the {@link Connection} is to
+         *                connect.
+         */
+        public Builder setAddress(Uri address) {
+            this.mAddress = address;
+            return this;
+        }
+
+        /**
+         * Sets the extras bundle for the resulting {@link ConnectionRequest}
+         * @param extras Application-specific extra data.
+         */
+        public Builder setExtras(Bundle extras) {
+            this.mExtras = extras;
+            return this;
+        }
+
+        /**
+         * Sets the video state for the resulting {@link ConnectionRequest}
+         * @param videoState Determines the video state for the connection.
+         */
+        public Builder setVideoState(int videoState) {
+            this.mVideoState = videoState;
+            return this;
+        }
+
+        /**
+         * Sets the Telecom call ID for the resulting {@link ConnectionRequest}
+         * @param telecomCallId The telecom call ID.
+         */
+        public Builder setTelecomCallId(String telecomCallId) {
+            this.mTelecomCallId = telecomCallId;
+            return this;
+        }
+
+        /**
+         * Sets shouldShowIncomingUi for the resulting {@link ConnectionRequest}
+         * @param shouldShowIncomingCallUi For a self-managed {@link ConnectionService}, will be
+         *                                 {@code true} if the {@link ConnectionService} should show
+         *                                 its own incoming call UI for an incoming call.  When
+         *                                 {@code false}, Telecom shows the incoming call UI.
+         */
+        public Builder setShouldShowIncomingCallUi(boolean shouldShowIncomingCallUi) {
+            this.mShouldShowIncomingCallUi = shouldShowIncomingCallUi;
+            return this;
+        }
+
+        /**
+         * Sets the RTT pipe for transferring text into the {@link ConnectionService} for the
+         * resulting {@link ConnectionRequest}
+         * @param rttPipeFromInCall The data pipe to read from.
+         */
+        public Builder setRttPipeFromInCall(ParcelFileDescriptor rttPipeFromInCall) {
+            this.mRttPipeFromInCall = rttPipeFromInCall;
+            return this;
+        }
+
+        /**
+         * Sets the RTT pipe for transferring text out of {@link ConnectionService} for the
+         * resulting {@link ConnectionRequest}
+         * @param rttPipeToInCall The data pipe to write to.
+         */
+        public Builder setRttPipeToInCall(ParcelFileDescriptor rttPipeToInCall) {
+            this.mRttPipeToInCall = rttPipeToInCall;
+            return this;
+        }
+
+        public ConnectionRequest build() {
+            return new ConnectionRequest(
+                    mAccountHandle,
+                    mAddress,
+                    mExtras,
+                    mVideoState,
+                    mTelecomCallId,
+                    mShouldShowIncomingCallUi,
+                    mRttPipeFromInCall,
+                    mRttPipeToInCall);
+        }
+    }
+
     private final PhoneAccountHandle mAccountHandle;
     private final Uri mAddress;
     private final Bundle mExtras;
     private final int mVideoState;
     private final String mTelecomCallId;
     private final boolean mShouldShowIncomingCallUi;
+    private final ParcelFileDescriptor mRttPipeToInCall;
+    private final ParcelFileDescriptor mRttPipeFromInCall;
 
     /**
      * @param accountHandle The accountHandle which should be used to place the call.
@@ -44,7 +153,7 @@
             PhoneAccountHandle accountHandle,
             Uri handle,
             Bundle extras) {
-        this(accountHandle, handle, extras, VideoProfile.STATE_AUDIO_ONLY, null, false);
+        this(accountHandle, handle, extras, VideoProfile.STATE_AUDIO_ONLY, null, false, null, null);
     }
 
     /**
@@ -58,7 +167,7 @@
             Uri handle,
             Bundle extras,
             int videoState) {
-        this(accountHandle, handle, extras, videoState, null, false);
+        this(accountHandle, handle, extras, videoState, null, false, null, null);
     }
 
     /**
@@ -80,12 +189,27 @@
             int videoState,
             String telecomCallId,
             boolean shouldShowIncomingCallUi) {
+        this(accountHandle, handle, extras, videoState, telecomCallId,
+                shouldShowIncomingCallUi, null, null);
+    }
+
+    private ConnectionRequest(
+            PhoneAccountHandle accountHandle,
+            Uri handle,
+            Bundle extras,
+            int videoState,
+            String telecomCallId,
+            boolean shouldShowIncomingCallUi,
+            ParcelFileDescriptor rttPipeFromInCall,
+            ParcelFileDescriptor rttPipeToInCall) {
         mAccountHandle = accountHandle;
         mAddress = handle;
         mExtras = extras;
         mVideoState = videoState;
         mTelecomCallId = telecomCallId;
         mShouldShowIncomingCallUi = shouldShowIncomingCallUi;
+        mRttPipeFromInCall = rttPipeFromInCall;
+        mRttPipeToInCall = rttPipeToInCall;
     }
 
     private ConnectionRequest(Parcel in) {
@@ -95,6 +219,8 @@
         mVideoState = in.readInt();
         mTelecomCallId = in.readString();
         mShouldShowIncomingCallUi = in.readInt() == 1;
+        mRttPipeFromInCall = in.readParcelable(getClass().getClassLoader());
+        mRttPipeToInCall = in.readParcelable(getClass().getClassLoader());
     }
 
     /**
@@ -149,6 +275,59 @@
         return mShouldShowIncomingCallUi;
     }
 
+    /**
+     * Gets the {@link ParcelFileDescriptor} that is used to send RTT text from the connection
+     * service to the in-call UI. In order to obtain an
+     * {@link java.io.InputStream} from this {@link ParcelFileDescriptor}, use
+     * {@link android.os.ParcelFileDescriptor.AutoCloseInputStream}.
+     * Only text data encoded using UTF-8 should be written into this {@link ParcelFileDescriptor}.
+     * @return The {@link ParcelFileDescriptor} that should be used for communication.
+     * Do not un-hide -- only for use by Telephony
+     * @hide
+     */
+    public ParcelFileDescriptor getRttPipeToInCall() {
+        return mRttPipeToInCall;
+    }
+
+    /**
+     * Gets the {@link ParcelFileDescriptor} that is used to send RTT text from the in-call UI to
+     * the connection service. In order to obtain an
+     * {@link java.io.OutputStream} from this {@link ParcelFileDescriptor}, use
+     * {@link android.os.ParcelFileDescriptor.AutoCloseOutputStream}.
+     * The contents of this {@link ParcelFileDescriptor} will consist solely of text encoded in
+     * UTF-8.
+     * @return The {@link ParcelFileDescriptor} that should be used for communication
+     * Do not un-hide -- only for use by Telephony
+     * @hide
+     */
+    public ParcelFileDescriptor getRttPipeFromInCall() {
+        return mRttPipeFromInCall;
+    }
+
+    /**
+     * Gets the {@link android.telecom.Connection.RttTextStream} object that should be used to
+     * send and receive RTT text to/from the in-call app.
+     * @return An instance of {@link android.telecom.Connection.RttTextStream}, or {@code null}
+     * if this connection request is not requesting an RTT session upon connection establishment.
+     * @hide
+     */
+    public Connection.RttTextStream getRttTextStream() {
+        if (isRequestingRtt()) {
+            return new Connection.RttTextStream(mRttPipeToInCall, mRttPipeFromInCall);
+        } else {
+            return null;
+        }
+    }
+
+    /**
+     * Convenience method for determining whether the ConnectionRequest is requesting an RTT session
+     * @return {@code true} if RTT is requested, {@code false} otherwise.
+     * @hide
+     */
+    public boolean isRequestingRtt() {
+        return mRttPipeFromInCall != null && mRttPipeToInCall != null;
+    }
+
     @Override
     public String toString() {
         return String.format("ConnectionRequest %s %s",
@@ -186,5 +365,7 @@
         destination.writeInt(mVideoState);
         destination.writeString(mTelecomCallId);
         destination.writeInt(mShouldShowIncomingCallUi ? 1 : 0);
+        destination.writeParcelable(mRttPipeFromInCall, 0);
+        destination.writeParcelable(mRttPipeToInCall, 0);
     }
 }
diff --git a/telecomm/java/android/telecom/InCallAdapter.java b/telecomm/java/android/telecom/InCallAdapter.java
index 3f270d9..d640b1d 100644
--- a/telecomm/java/android/telecom/InCallAdapter.java
+++ b/telecomm/java/android/telecom/InCallAdapter.java
@@ -34,7 +34,7 @@
  * <p>
  * The adapter will stop functioning when there are no more calls.
  *
- * {@hide}
+ * @hide
  */
 public final class InCallAdapter {
     private final IInCallAdapter mAdapter;
@@ -375,4 +375,48 @@
         } catch (RemoteException ignored) {
         }
     }
+
+    /**
+     * Sends an RTT upgrade request to the remote end of the connection.
+     */
+    public void sendRttRequest() {
+        try {
+            mAdapter.sendRttRequest();
+        } catch (RemoteException ignored) {
+        }
+    }
+
+    /**
+     * Responds to an RTT upgrade request initiated from the remote end.
+     *
+     * @param id the ID of the request as specified by Telecom
+     * @param accept Whether the request should be accepted.
+     */
+    public void respondToRttRequest(int id, boolean accept) {
+        try {
+            mAdapter.respondToRttRequest(id, accept);
+        } catch (RemoteException ignored) {
+        }
+    }
+
+    /**
+     * Instructs Telecom to shut down the RTT communication channel.
+     */
+    public void stopRtt() {
+        try {
+            mAdapter.stopRtt();
+        } catch (RemoteException ignored) {
+        }
+    }
+
+    /**
+     * Sets the RTT audio mode.
+     * @param mode the desired RTT audio mode
+     */
+    public void setRttMode(int mode) {
+        try {
+            mAdapter.setRttMode(mode);
+        } catch (RemoteException ignored) {
+        }
+    }
 }
diff --git a/telecomm/java/android/telecom/InCallService.java b/telecomm/java/android/telecom/InCallService.java
index 5d68aae..4bc64c0 100644
--- a/telecomm/java/android/telecom/InCallService.java
+++ b/telecomm/java/android/telecom/InCallService.java
@@ -76,6 +76,7 @@
     private static final int MSG_ON_CAN_ADD_CALL_CHANGED = 7;
     private static final int MSG_SILENCE_RINGER = 8;
     private static final int MSG_ON_CONNECTION_EVENT = 9;
+    private static final int MSG_ON_RTT_UPGRADE_REQUEST = 10;
 
     /** Default Handler used to consolidate binder method calls onto a single thread. */
     private final Handler mHandler = new Handler(Looper.getMainLooper()) {
@@ -133,6 +134,12 @@
                     }
                     break;
                 }
+                case MSG_ON_RTT_UPGRADE_REQUEST: {
+                    String callId = (String) msg.obj;
+                    int requestId = msg.arg1;
+                    mPhone.internalOnRttUpgradeRequest(callId, requestId);
+                    break;
+                }
                 default:
                     break;
             }
@@ -198,6 +205,11 @@
             args.arg3 = extras;
             mHandler.obtainMessage(MSG_ON_CONNECTION_EVENT, args).sendToTarget();
         }
+
+        @Override
+        public void onRttUpgradeRequest(String callId, int id) {
+            mHandler.obtainMessage(MSG_ON_RTT_UPGRADE_REQUEST, id, 0, callId).sendToTarget();
+        }
     }
 
     private Phone.Listener mPhoneListener = new Phone.Listener() {
diff --git a/telecomm/java/android/telecom/ParcelableCall.java b/telecomm/java/android/telecom/ParcelableCall.java
index a3fce9c..975aa5a 100644
--- a/telecomm/java/android/telecom/ParcelableCall.java
+++ b/telecomm/java/android/telecom/ParcelableCall.java
@@ -50,6 +50,8 @@
     private final boolean mIsVideoCallProviderChanged;
     private final IVideoProvider mVideoCallProvider;
     private VideoCallImpl mVideoCall;
+    private final boolean mIsRttCallChanged;
+    private final ParcelableRttCall mRttCall;
     private final String mParentCallId;
     private final List<String> mChildCallIds;
     private final StatusHints mStatusHints;
@@ -75,6 +77,8 @@
             PhoneAccountHandle accountHandle,
             boolean isVideoCallProviderChanged,
             IVideoProvider videoCallProvider,
+            boolean isRttCallChanged,
+            ParcelableRttCall rttCall,
             String parentCallId,
             List<String> childCallIds,
             StatusHints statusHints,
@@ -98,6 +102,8 @@
         mAccountHandle = accountHandle;
         mIsVideoCallProviderChanged = isVideoCallProviderChanged;
         mVideoCallProvider = videoCallProvider;
+        mIsRttCallChanged = isRttCallChanged;
+        mRttCall = rttCall;
         mParentCallId = parentCallId;
         mChildCallIds = childCallIds;
         mStatusHints = statusHints;
@@ -202,6 +208,18 @@
         return mVideoCall;
     }
 
+    public boolean getIsRttCallChanged() {
+        return mIsRttCallChanged;
+    }
+
+    /**
+     * RTT communication channel information
+     * @return The ParcelableRttCall
+     */
+    public ParcelableRttCall getParcelableRttCall() {
+        return mRttCall;
+    }
+
     /**
      * The conference call to which this call is conferenced. Null if not conferenced.
      */
@@ -301,6 +319,8 @@
             Bundle intentExtras = source.readBundle(classLoader);
             Bundle extras = source.readBundle(classLoader);
             int supportedAudioRoutes = source.readInt();
+            boolean isRttCallChanged = source.readByte() == 1;
+            ParcelableRttCall rttCall = source.readParcelable(classLoader);
             return new ParcelableCall(
                     id,
                     state,
@@ -318,6 +338,8 @@
                     accountHandle,
                     isVideoCallProviderChanged,
                     videoCallProvider,
+                    isRttCallChanged,
+                    rttCall,
                     parentCallId,
                     childCallIds,
                     statusHints,
@@ -366,6 +388,8 @@
         destination.writeBundle(mIntentExtras);
         destination.writeBundle(mExtras);
         destination.writeInt(mSupportedAudioRoutes);
+        destination.writeByte((byte) (mIsRttCallChanged ? 1 : 0));
+        destination.writeParcelable(mRttCall, 0);
     }
 
     @Override
diff --git a/telecomm/java/android/telecom/ParcelableRttCall.aidl b/telecomm/java/android/telecom/ParcelableRttCall.aidl
new file mode 100644
index 0000000..4480710
--- /dev/null
+++ b/telecomm/java/android/telecom/ParcelableRttCall.aidl
@@ -0,0 +1,22 @@
+/*
+ * Copyright 2017, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.telecom;
+
+/**
+ * {@hide}
+ */
+parcelable ParcelableRttCall;
diff --git a/telecomm/java/android/telecom/ParcelableRttCall.java b/telecomm/java/android/telecom/ParcelableRttCall.java
new file mode 100644
index 0000000..763e48b
--- /dev/null
+++ b/telecomm/java/android/telecom/ParcelableRttCall.java
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package android.telecom;
+
+import android.os.Parcel;
+import android.os.ParcelFileDescriptor;
+import android.os.Parcelable;
+
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.nio.charset.StandardCharsets;
+
+/**
+ * Data container for information associated with the RTT connection on a call.
+ * @hide
+ */
+public class ParcelableRttCall implements Parcelable {
+    private final int mRttMode;
+    private final ParcelFileDescriptor mTransmitStream;
+    private final ParcelFileDescriptor mReceiveStream;
+
+    public ParcelableRttCall(
+            int rttMode,
+            ParcelFileDescriptor transmitStream,
+            ParcelFileDescriptor receiveStream) {
+        mRttMode = rttMode;
+        mTransmitStream = transmitStream;
+        mReceiveStream = receiveStream;
+    }
+
+    protected ParcelableRttCall(Parcel in) {
+        mRttMode = in.readInt();
+        mTransmitStream = in.readParcelable(ParcelFileDescriptor.class.getClassLoader());
+        mReceiveStream = in.readParcelable(ParcelFileDescriptor.class.getClassLoader());
+    }
+
+    public static final Creator<ParcelableRttCall> CREATOR = new Creator<ParcelableRttCall>() {
+        @Override
+        public ParcelableRttCall createFromParcel(Parcel in) {
+            return new ParcelableRttCall(in);
+        }
+
+        @Override
+        public ParcelableRttCall[] newArray(int size) {
+            return new ParcelableRttCall[size];
+        }
+    };
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeInt(mRttMode);
+        dest.writeParcelable(mTransmitStream, flags);
+        dest.writeParcelable(mReceiveStream, flags);
+    }
+
+    public int getRttMode() {
+        return mRttMode;
+    }
+
+    public ParcelFileDescriptor getReceiveStream() {
+        return mReceiveStream;
+    }
+
+    public ParcelFileDescriptor getTransmitStream() {
+        return mTransmitStream;
+    }
+}
diff --git a/telecomm/java/android/telecom/Phone.java b/telecomm/java/android/telecom/Phone.java
index 30ec5b3..ebd04c7 100644
--- a/telecomm/java/android/telecom/Phone.java
+++ b/telecomm/java/android/telecom/Phone.java
@@ -201,6 +201,13 @@
         }
     }
 
+    final void internalOnRttUpgradeRequest(String callId, int requestId) {
+        Call call = mCallByTelecomCallId.get(callId);
+        if (call != null) {
+            call.internalOnRttUpgradeRequest(requestId);
+        }
+    }
+
     /**
      * Called to destroy the phone and cleanup any lingering calls.
      */
diff --git a/telecomm/java/android/telecom/PhoneAccount.java b/telecomm/java/android/telecom/PhoneAccount.java
index 845a103..3926e20 100644
--- a/telecomm/java/android/telecom/PhoneAccount.java
+++ b/telecomm/java/android/telecom/PhoneAccount.java
@@ -204,6 +204,18 @@
     public static final int CAPABILITY_SELF_MANAGED = 0x800;
 
     /**
+     * Flag indicating that this {@link PhoneAccount} is capable of making a call with an
+     * RTT (Real-time text) session.
+     * When set, Telecom will attempt to open an RTT session on outgoing calls that specify
+     * that they should be placed with an RTT session , and the in-call app will be displayed
+     * with text entry fields for RTT. Likewise, the in-call app can request that an RTT
+     * session be opened during a call if this bit is set.
+     */
+    public static final int CAPABILITY_RTT = 0x1000;
+
+    /* NEXT CAPABILITY: 0x2000 */
+
+    /**
      * URI scheme for telephone number URIs.
      */
     public static final String SCHEME_TEL = "tel";
diff --git a/telecomm/java/android/telecom/RemoteConnectionService.java b/telecomm/java/android/telecom/RemoteConnectionService.java
index 0c7404a..60a40f5 100644
--- a/telecomm/java/android/telecom/RemoteConnectionService.java
+++ b/telecomm/java/android/telecom/RemoteConnectionService.java
@@ -450,11 +450,14 @@
             ConnectionRequest request,
             boolean isIncoming) {
         final String id = UUID.randomUUID().toString();
-        final ConnectionRequest newRequest = new ConnectionRequest(
-                request.getAccountHandle(),
-                request.getAddress(),
-                request.getExtras(),
-                request.getVideoState());
+        final ConnectionRequest newRequest = new ConnectionRequest.Builder()
+                .setAccountHandle(request.getAccountHandle())
+                .setAddress(request.getAddress())
+                .setExtras(request.getExtras())
+                .setVideoState(request.getVideoState())
+                .setRttPipeFromInCall(request.getRttPipeFromInCall())
+                .setRttPipeToInCall(request.getRttPipeToInCall())
+                .build();
         try {
             if (mConnectionById.isEmpty()) {
                 mOutgoingConnectionServiceRpc.addConnectionServiceAdapter(mServant.getStub(),
diff --git a/telecomm/java/android/telecom/TelecomManager.java b/telecomm/java/android/telecom/TelecomManager.java
index 7964cf2..6807ef4 100644
--- a/telecomm/java/android/telecom/TelecomManager.java
+++ b/telecomm/java/android/telecom/TelecomManager.java
@@ -326,6 +326,14 @@
             "android.telecom.extra.NEW_OUTGOING_CALL_CANCEL_TIMEOUT";
 
     /**
+     * A boolean extra, which when set on the {@link Intent#ACTION_CALL} intent or on the bundle
+     * passed into {@link #placeCall(Uri, Bundle)}, indicates that the call should be initiated with
+     * an RTT session open. See {@link android.telecom.Call.RttCall} for more information on RTT.
+     */
+    public static final String EXTRA_START_CALL_WITH_RTT =
+            "android.telecom.extra.START_CALL_WITH_RTT";
+
+    /**
      * A boolean meta-data value indicating whether an {@link InCallService} implements an
      * in-call user interface. Dialer implementations (see {@link #getDefaultDialerPackage()}) which
      * would also like to replace the in-call interface should set this meta-data to {@code true} in
diff --git a/telecomm/java/com/android/internal/telecom/IInCallAdapter.aidl b/telecomm/java/com/android/internal/telecom/IInCallAdapter.aidl
index 49f9b3b..47c3e6c 100644
--- a/telecomm/java/com/android/internal/telecom/IInCallAdapter.aidl
+++ b/telecomm/java/com/android/internal/telecom/IInCallAdapter.aidl
@@ -69,4 +69,12 @@
     void putExtras(String callId, in Bundle extras);
 
     void removeExtras(String callId, in List<String> keys);
+
+    void sendRttRequest();
+
+    void respondToRttRequest(int id, boolean accept);
+
+    void stopRtt();
+
+    void setRttMode(int mode);
 }
diff --git a/telecomm/java/com/android/internal/telecom/IInCallService.aidl b/telecomm/java/com/android/internal/telecom/IInCallService.aidl
index 3e43fe2..1f92e0c 100644
--- a/telecomm/java/com/android/internal/telecom/IInCallService.aidl
+++ b/telecomm/java/com/android/internal/telecom/IInCallService.aidl
@@ -50,4 +50,6 @@
     void silenceRinger();
 
     void onConnectionEvent(String callId, String event, in Bundle extras);
+
+    void onRttUpgradeRequest(String callId, int id);
 }