diff --git a/app/src/main/kotlin/com/tutpro/baresip/BaresipService.kt b/app/src/main/kotlin/com/tutpro/baresip/BaresipService.kt
index ff2fe6f4..3009282e 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/BaresipService.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/BaresipService.kt
@@ -520,7 +520,8 @@ class BaresipService: Service() {
                     }
                     "call outgoing" -> {
                         stopMediaPlayer()
-                        am.mode = AudioManager.MODE_IN_COMMUNICATION
+                        if (am.mode != AudioManager.MODE_IN_COMMUNICATION)
+                            am.mode = AudioManager.MODE_IN_COMMUNICATION
                         requestAudioFocus(AudioAttributes.USAGE_VOICE_COMMUNICATION,
                             AudioAttributes.CONTENT_TYPE_SPEECH)
                         setCallVolume()
@@ -757,7 +758,6 @@ class BaresipService: Service() {
                             am.isSpeakerphoneOn = false
                             am.stopBluetoothSco()
                             abandonAudioFocus()
-                            am.mode = AudioManager.MODE_NORMAL
                             proximitySensing(false)
                         }
                         if (ua.account.callHistory && !call.hasHistory) {
diff --git a/app/src/main/kotlin/com/tutpro/baresip/MainActivity.kt b/app/src/main/kotlin/com/tutpro/baresip/MainActivity.kt
index 796d6228..9d2eebc3 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/MainActivity.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/MainActivity.kt
@@ -792,6 +792,9 @@ class MainActivity : AppCompatActivity() {
         super.onResume()
         Log.d(TAG, "Main onResume with action '$resumeAction'")
         nm.cancelAll()
+        // Keep the app in communication mode in order to avoid audio delay when the mode changes
+        if (am.mode != AudioManager.MODE_RINGTONE && am.mode != AudioManager.MODE_IN_COMMUNICATION)
+            am.mode = AudioManager.MODE_IN_COMMUNICATION
         visible = true
         when (resumeAction) {
             "call show" ->
diff --git a/app/src/main/res/raw/ringback.wav b/app/src/main/res/raw/ringback.wav
index 4e5fd9bb..7b3f8195 100644
Binary files a/app/src/main/res/raw/ringback.wav and b/app/src/main/res/raw/ringback.wav differ