diff --git a/telephony/java/android/telephony/CarrierConfigManager.java b/telephony/java/android/telephony/CarrierConfigManager.java
index 4fcda6393a56e..7d9462adbc796 100755
--- a/telephony/java/android/telephony/CarrierConfigManager.java
+++ b/telephony/java/android/telephony/CarrierConfigManager.java
@@ -1025,6 +1025,18 @@ public class CarrierConfigManager {
     public static final String KEY_CALL_FORWARDING_MAP_NON_NUMBER_TO_VOICEMAIL_BOOL =
             "call_forwarding_map_non_number_to_voicemail_bool";
 
+    /**
+     * When {@code true}, the phone will always tell the IMS stack to keep RTT enabled and
+     * determine on a per-call basis (based on extras from the dialer app) whether a call should be
+     * an RTT call or not.
+     *
+     * When {@code false}, the old behavior is used, where the toggle in accessibility settings is
+     * used to set the IMS stack's RTT enabled state.
+     * @hide
+     */
+    public static final String KEY_IGNORE_RTT_MODE_SETTING_BOOL =
+            "ignore_rtt_mode_setting_bool";
+
     /**
      * Determines whether conference calls are supported by a carrier.  When {@code true},
      * conference calling is supported, {@code false otherwise}.
@@ -3306,6 +3318,7 @@ public class CarrierConfigManager {
         sDefaults.putInt(KEY_IMS_DTMF_TONE_DELAY_INT, 0);
         sDefaults.putInt(KEY_CDMA_DTMF_TONE_DELAY_INT, 100);
         sDefaults.putBoolean(KEY_CALL_FORWARDING_MAP_NON_NUMBER_TO_VOICEMAIL_BOOL, false);
+        sDefaults.putBoolean(KEY_IGNORE_RTT_MODE_SETTING_BOOL, false);
         sDefaults.putInt(KEY_CDMA_3WAYCALL_FLASH_DELAY_INT , 0);
         sDefaults.putBoolean(KEY_SUPPORT_CONFERENCE_CALL_BOOL, true);
         sDefaults.putBoolean(KEY_SUPPORT_IMS_CONFERENCE_CALL_BOOL, true);