diff --git a/src/com/android/phone/CdmaCallOptions.java b/src/com/android/phone/CdmaCallOptions.java
index a2bc9cb..8f4fa67 100644
--- a/src/com/android/phone/CdmaCallOptions.java
+++ b/src/com/android/phone/CdmaCallOptions.java
@@ -27,12 +27,13 @@
 
 import com.android.internal.telephony.PhoneConstants;
 
-public class CdmaCallOptions extends PreferenceActivity {
+public class CdmaCallOptions extends TimeConsumingPreferenceActivity {
     private static final String LOG_TAG = "CdmaCallOptions";
     private final boolean DBG = (PhoneGlobals.DBG_LEVEL >= 2);
 
     private static final String BUTTON_VP_KEY = "button_voice_privacy_key";
     private static final String CALL_FORWARDING_KEY = "call_forwarding_key";
+    private static final String CALL_WAITING_KEY = "call_waiting_key";
     private SwitchPreference mButtonVoicePrivacy;
 
     @Override
@@ -61,6 +62,10 @@
 
         Preference callForwardingPref = getPreferenceScreen().findPreference(CALL_FORWARDING_KEY);
         callForwardingPref.setIntent(subInfoHelper.getIntent(CdmaCallForwardOptions.class));
+
+        CdmaCallWaitingPreference callWaitingPref = (CdmaCallWaitingPreference)getPreferenceScreen()
+                                                     .findPreference(CALL_WAITING_KEY);
+        callWaitingPref.init(this, subInfoHelper.getPhone());
     }
 
     @Override
@@ -80,5 +85,4 @@
         }
         return false;
     }
-
 }
diff --git a/src/com/android/phone/CdmaCallWaitingPreference.java b/src/com/android/phone/CdmaCallWaitingPreference.java
new file mode 100644
index 0000000..4cda7ba
--- /dev/null
+++ b/src/com/android/phone/CdmaCallWaitingPreference.java
@@ -0,0 +1,194 @@
+/*
+ * Copyright (C) 2020 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 com.android.phone;
+
+import com.android.internal.telephony.CommandException;
+import com.android.internal.telephony.CommandsInterface;
+import com.android.internal.telephony.Phone;
+
+import android.app.AlertDialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.res.TypedArray;
+import android.os.AsyncResult;
+import android.os.Handler;
+import android.os.Message;
+import android.preference.Preference;
+import android.preference.PreferenceActivity;
+import android.util.AttributeSet;
+import android.util.Log;
+
+public class CdmaCallWaitingPreference extends Preference {
+    private static final String LOG_TAG = "CdmaCallWaitingPreference";
+    private static final boolean DBG = (PhoneGlobals.DBG_LEVEL >= 2);
+
+    private int mButtonClicked;
+    private Context mContext;
+    private Phone mPhone;
+    private SubscriptionInfoHelper mSubscriptionInfoHelper;
+    private TimeConsumingPreferenceListener mTcpListener;
+    private MyHandler mHandler = new MyHandler();
+
+    public CdmaCallWaitingPreference(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+        mContext = context;
+    }
+
+    public CdmaCallWaitingPreference(Context context, AttributeSet attrs) {
+        this(context, attrs, com.android.internal.R.attr.preferenceStyle);
+    }
+
+    public CdmaCallWaitingPreference(Context context) {
+        this(context, null);
+    }
+
+    public void init(TimeConsumingPreferenceListener listener, Phone phone) {
+        mPhone = phone;
+        mTcpListener = listener;
+        Log.d(LOG_TAG, "phone id= " + mPhone.getPhoneId());
+        mPhone.getCallWaiting(mHandler.obtainMessage(MyHandler.MESSAGE_GET_CALL_WAITING,
+                    MyHandler.MESSAGE_GET_CALL_WAITING, MyHandler.MESSAGE_GET_CALL_WAITING));
+        if (mTcpListener != null) {
+            mTcpListener.onStarted(this, true);
+        }
+    }
+
+    @Override
+    public void onClick() {
+        super.onClick();
+
+        AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
+        builder.setTitle(mContext.getText(R.string.cdma_call_waiting));
+        builder.setMessage(mContext.getText(R.string.enable_cdma_call_waiting_setting));
+        builder.setPositiveButton(R.string.enable_cdma_cw, new DialogInterface.OnClickListener() {
+            public void onClick(DialogInterface dialog, int whichButton) {
+                mPhone.setCallWaiting(true,
+                        mHandler.obtainMessage(MyHandler.MESSAGE_SET_CALL_WAITING));
+                if (mTcpListener != null) {
+                    mTcpListener.onStarted(CdmaCallWaitingPreference.this, false);
+                }
+            }
+        });
+        builder.setNegativeButton(R.string.disable_cdma_cw, new DialogInterface.OnClickListener() {
+            public void onClick(DialogInterface dialog, int whichButton) {
+                mPhone.setCallWaiting(false,
+                        mHandler.obtainMessage(MyHandler.MESSAGE_SET_CALL_WAITING));
+                if (mTcpListener != null) {
+                    mTcpListener.onStarted(CdmaCallWaitingPreference.this, false);
+                }
+            }
+        });
+        builder.create().show();
+    }
+
+    private class MyHandler extends Handler {
+        static final int MESSAGE_GET_CALL_WAITING = 0;
+        static final int MESSAGE_SET_CALL_WAITING = 1;
+
+        @Override
+        public void handleMessage(Message msg) {
+            switch (msg.what) {
+                case MESSAGE_GET_CALL_WAITING:
+                    handleGetCallWaitingResponse(msg);
+                    break;
+                case MESSAGE_SET_CALL_WAITING:
+                    handleSetCallWaitingResponse(msg);
+                    break;
+            }
+        }
+
+        private void handleGetCallWaitingResponse(Message msg) {
+            AsyncResult ar = (AsyncResult) msg.obj;
+
+            if (mTcpListener != null) {
+                if (msg.arg2 == MESSAGE_SET_CALL_WAITING) {
+                    mTcpListener.onFinished(CdmaCallWaitingPreference.this, false);
+                } else {
+                    mTcpListener.onFinished(CdmaCallWaitingPreference.this, true);
+                }
+            }
+
+            if (ar.exception instanceof CommandException) {
+                if (DBG) {
+                    Log.d(LOG_TAG, "handleGetCallWaitingResponse: CommandException=" +
+                            ar.exception);
+                }
+                if (mTcpListener != null) {
+                    mTcpListener.onException(CdmaCallWaitingPreference.this,
+                                             (CommandException)ar.exception);
+                }
+            } else if (ar.userObj instanceof Throwable || ar.exception != null) {
+                if (DBG) {
+                    Log.d(LOG_TAG, "handleGetCallWaitingResponse: Exception" + ar.exception);
+                }
+                if (mTcpListener != null) {
+                    mTcpListener.onError(CdmaCallWaitingPreference.this,
+                                         TimeConsumingPreferenceActivity.RESPONSE_ERROR);
+                }
+            } else {
+                if (DBG) {
+                    Log.d(LOG_TAG, "handleGetCallWaitingResponse: CW state successfully queried.");
+                }
+                int[] cwArray = (int[])ar.result;
+                if (cwArray == null) {
+                    if (mTcpListener != null) {
+                        mTcpListener.onError(CdmaCallWaitingPreference.this,
+                                             TimeConsumingPreferenceActivity.RESPONSE_ERROR);
+                    }
+                    return;
+                }
+
+                try {
+                    if (cwArray[0] == CommandsInterface.SS_STATUS_UNKNOWN) {
+                        setSummary("");
+                    } else if(cwArray[0] == 1) {
+                        setSummary(mContext.getString(R.string.cdma_call_waiting_in_ims_on));
+                    } else if(cwArray[0] == 0) {
+                        setSummary(mContext.getString(R.string.cdma_call_waiting_in_ims_off));
+                    }
+                } catch (ArrayIndexOutOfBoundsException e) {
+                    setSummary("");
+                    Log.e(LOG_TAG, "handleGetCallWaitingResponse: improper result: err ="
+                            + e.getMessage());
+                }
+            }
+        }
+
+        private void handleSetCallWaitingResponse(Message msg) {
+            AsyncResult ar = (AsyncResult) msg.obj;
+
+            if (ar.exception != null) {
+                if (DBG) {
+                    Log.d(LOG_TAG, "handleSetCallWaitingResponse: ar.exception=" + ar.exception);
+                }
+            }
+
+            if (ar.result != null) {
+                int arr = (int)ar.result;
+                if (arr == CommandsInterface.SS_STATUS_UNKNOWN) {
+                    Log.d(LOG_TAG, "handleSetCallWaitingResponse: no need to re get in CDMA");
+                    mTcpListener.onFinished(CdmaCallWaitingPreference.this, false);
+                    return;
+                }
+            }
+
+            if (DBG) Log.d(LOG_TAG, "handleSetCallWaitingResponse: re get");
+            mPhone.getCallWaiting(obtainMessage(MESSAGE_GET_CALL_WAITING,
+                        MESSAGE_SET_CALL_WAITING, MESSAGE_SET_CALL_WAITING, ar.exception));
+        }
+    }
+}