diff --git a/dom/html/HTMLMediaElement.cpp b/dom/html/HTMLMediaElement.cpp
index a2471b67b9e4..493bbd26678a 100644
--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -2055,8 +2055,7 @@ HTMLMediaElement::HTMLMediaElement(already_AddRefed<mozilla::dom::NodeInfo>& aNo
     mPlayingThroughTheAudioChannel(false),
     mDisableVideo(false),
     mPlayBlockedBecauseHidden(false),
-    mElementInTreeState(ELEMENT_NOT_INTREE),
-    mHaveDispatchedInterruptBeginEvent(false)
+    mElementInTreeState(ELEMENT_NOT_INTREE)
 {
   if (!gMediaElementLog) {
     gMediaElementLog = PR_NewLogModule("nsMediaElement");
@@ -4452,12 +4451,10 @@ nsresult HTMLMediaElement::UpdateChannelMuteState(float aVolume, bool aMuted)
     SetMutedInternal(mMuted | MUTED_BY_AUDIO_CHANNEL);
     if (UseAudioChannelAPI()) {
       DispatchAsyncEvent(NS_LITERAL_STRING("mozinterruptbegin"));
-      mHaveDispatchedInterruptBeginEvent = true;
     }
   } else if (!aMuted && ComputedMuted()) {
     SetMutedInternal(mMuted & ~MUTED_BY_AUDIO_CHANNEL);
-    if (UseAudioChannelAPI() && mHaveDispatchedInterruptBeginEvent) {
-      mHaveDispatchedInterruptBeginEvent = false;
+    if (UseAudioChannelAPI()) {
       DispatchAsyncEvent(NS_LITERAL_STRING("mozinterruptend"));
     }
   }
diff --git a/dom/html/HTMLMediaElement.h b/dom/html/HTMLMediaElement.h
index 80aeac5a5c20..84f4ed0d9cd8 100644
--- a/dom/html/HTMLMediaElement.h
+++ b/dom/html/HTMLMediaElement.h
@@ -1414,8 +1414,6 @@ protected:
 
   ElementInTreeState mElementInTreeState;
 
-  bool mHaveDispatchedInterruptBeginEvent;
-
 public:
   // Helper class to measure times for MSE telemetry stats
   class TimeDurationAccumulator {
diff --git a/dom/media/webaudio/AudioDestinationNode.cpp b/dom/media/webaudio/AudioDestinationNode.cpp
index a7c328d4f41f..95ab1b413459 100644
--- a/dom/media/webaudio/AudioDestinationNode.cpp
+++ b/dom/media/webaudio/AudioDestinationNode.cpp
@@ -326,7 +326,6 @@ AudioDestinationNode::AudioDestinationNode(AudioContext* aContext,
   , mExtraCurrentTime(0)
   , mExtraCurrentTimeSinceLastStartedBlocking(0)
   , mExtraCurrentTimeUpdatedSinceLastStableState(false)
-  , mHaveDispatchedInterruptBeginEvent(false)
 {
   bool startWithAudioDriver = true;
   MediaStreamGraph* graph = aIsOffline ?
@@ -495,12 +494,10 @@ AudioDestinationNode::WindowVolumeChanged(float aVolume, bool aMuted)
   if (aMuted != mAudioChannelAgentPlaying) {
     mAudioChannelAgentPlaying = aMuted;
 
-    if (UseAudioChannelAPI() &&
-        (mHaveDispatchedInterruptBeginEvent || aMuted)) {
+    if (UseAudioChannelAPI()) {
       Context()->DispatchTrustedEvent(
         !aMuted ? NS_LITERAL_STRING("mozinterruptend")
                 : NS_LITERAL_STRING("mozinterruptbegin"));
-      mHaveDispatchedInterruptBeginEvent = aMuted;
     }
   }
 
diff --git a/dom/media/webaudio/AudioDestinationNode.h b/dom/media/webaudio/AudioDestinationNode.h
index 9fecfbb19d78..db5418a9cb51 100644
--- a/dom/media/webaudio/AudioDestinationNode.h
+++ b/dom/media/webaudio/AudioDestinationNode.h
@@ -111,7 +111,6 @@ private:
   double mExtraCurrentTime;
   double mExtraCurrentTimeSinceLastStartedBlocking;
   bool mExtraCurrentTimeUpdatedSinceLastStableState;
-  bool mHaveDispatchedInterruptBeginEvent;
 };
 
 } // namespace dom
diff --git a/dom/telephony/Telephony.cpp b/dom/telephony/Telephony.cpp
index 1349b6e464fb..d3146b5890b2 100644
--- a/dom/telephony/Telephony.cpp
+++ b/dom/telephony/Telephony.cpp
@@ -21,7 +21,7 @@
 #include "nsServiceManagerUtils.h"
 #include "nsThreadUtils.h"
 
-#include "AudioChannelService.h"
+#include "AudioChannelAgent.h"
 #include "CallsList.h"
 #include "TelephonyCall.h"
 #include "TelephonyCallGroup.h"
@@ -65,8 +65,7 @@ public:
 
 Telephony::Telephony(nsPIDOMWindow* aOwner)
   : DOMEventTargetHelper(aOwner),
-    mIsAudioStartPlaying(false),
-    mHaveDispatchedInterruptBeginEvent(false)
+    mIsAudioStartPlaying(false)
 {
   MOZ_ASSERT(aOwner);
   nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aOwner);
@@ -77,7 +76,6 @@ Telephony::Telephony(nsPIDOMWindow* aOwner)
   MOZ_ASSERT(!rv.Failed());
 
   mReadyPromise = promise;
-  mMuted = AudioChannelService::IsAudioChannelMutedByDefault();
 }
 
 Telephony::~Telephony()
@@ -682,21 +680,6 @@ Telephony::WindowVolumeChanged(float aVolume, bool aMuted)
     return rv.StealNSResult();
   }
 
-  // These events will be triggered when the telephony is interrupted by other
-  // audio channel.
-  if (mMuted != aMuted) {
-    mMuted = aMuted;
-    // We should not dispatch "mozinterruptend" when the system app initializes
-    // the telephony audio from muted to unmuted at the first time. The event
-    // "mozinterruptend" must be dispatched after the "mozinterruptbegin".
-    if (!mHaveDispatchedInterruptBeginEvent && mMuted) {
-      DispatchTrustedEvent(NS_LITERAL_STRING("mozinterruptbegin"));
-      mHaveDispatchedInterruptBeginEvent = mMuted;
-    } else if (mHaveDispatchedInterruptBeginEvent && !mMuted) {
-      DispatchTrustedEvent(NS_LITERAL_STRING("mozinterruptend"));
-      mHaveDispatchedInterruptBeginEvent = mMuted;
-    }
-  }
   return NS_OK;
 }
 
diff --git a/dom/telephony/Telephony.h b/dom/telephony/Telephony.h
index d4a84e1615d9..f295461414e8 100644
--- a/dom/telephony/Telephony.h
+++ b/dom/telephony/Telephony.h
@@ -59,8 +59,6 @@ class Telephony final : public DOMEventTargetHelper,
   nsRefPtr<Promise> mReadyPromise;
 
   bool mIsAudioStartPlaying;
-  bool mHaveDispatchedInterruptBeginEvent;
-  bool mMuted;
 
 public:
   NS_DECL_ISUPPORTS_INHERITED