diff --git a/telephony/java/android/telephony/CallState.java b/telephony/java/android/telephony/CallState.java
index 51ecfb0a0be84..836cb53488ef7 100644
--- a/telephony/java/android/telephony/CallState.java
+++ b/telephony/java/android/telephony/CallState.java
@@ -285,12 +285,12 @@ public final class CallState implements Parcelable {
     /**
      * Builder of {@link CallState}
      *
-     * <p>The example below shows how you might create a new {@code CallState}:
+     * <p>The example below shows how you might create a new {@code CallState}. A precise call state
+     * {@link PreciseCallStates} is mandatory to build a CallState.
      *
      * <pre><code>
      *
-     * CallState = new CallState.Builder()
-     *     .setCallState(3)
+     * CallState = new CallState.Builder({@link PreciseCallStates})
      *     .setNetworkType({@link TelephonyManager#NETWORK_TYPE_LTE})
      *     .setCallQuality({@link CallQuality})
      *     .setImsCallSessionId({@link String})
diff --git a/telephony/java/android/telephony/ims/ImsCallProfile.java b/telephony/java/android/telephony/ims/ImsCallProfile.java
index 1ea7fdc982a55..d07edeb971ea0 100644
--- a/telephony/java/android/telephony/ims/ImsCallProfile.java
+++ b/telephony/java/android/telephony/ims/ImsCallProfile.java
@@ -27,6 +27,7 @@ import android.os.Bundle;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.telecom.VideoProfile;
+import android.telephony.CallState;
 import android.telephony.emergency.EmergencyNumber;
 import android.telephony.emergency.EmergencyNumber.EmergencyCallRouting;
 import android.telephony.emergency.EmergencyNumber.EmergencyServiceCategories;
@@ -78,7 +79,9 @@ public final class ImsCallProfile implements Parcelable {
     public static final int SERVICE_TYPE_EMERGENCY = 2;
 
     /**
-     * Call type none
+     * This value is returned if there is no valid IMS call type defined for the call. For example,
+     * if an ongoing call is circuit-switched and {@link CallState#getImsCallType()} is called, this
+     * value will be returned.
      */
     public static final int CALL_TYPE_NONE = 0;
     /**