diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/pipeline/mobile/data/model/DataConnectionState.kt b/packages/SystemUI/src/com/android/systemui/statusbar/pipeline/mobile/data/model/DataConnectionState.kt
index da87f7306e601..5479b92edd222 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/pipeline/mobile/data/model/DataConnectionState.kt
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/pipeline/mobile/data/model/DataConnectionState.kt
@@ -20,6 +20,7 @@ import android.telephony.TelephonyManager.DATA_CONNECTED
 import android.telephony.TelephonyManager.DATA_CONNECTING
 import android.telephony.TelephonyManager.DATA_DISCONNECTED
 import android.telephony.TelephonyManager.DATA_DISCONNECTING
+import android.telephony.TelephonyManager.DATA_UNKNOWN
 import android.telephony.TelephonyManager.DataState
 
 /** Internal enum representation of the telephony data connection states */
@@ -28,6 +29,7 @@ enum class DataConnectionState(@DataState val dataState: Int) {
     Connecting(DATA_CONNECTING),
     Disconnected(DATA_DISCONNECTED),
     Disconnecting(DATA_DISCONNECTING),
+    Unknown(DATA_UNKNOWN),
 }
 
 fun @receiver:DataState Int.toDataConnectionType(): DataConnectionState =
@@ -36,5 +38,6 @@ fun @receiver:DataState Int.toDataConnectionType(): DataConnectionState =
         DATA_CONNECTING -> DataConnectionState.Connecting
         DATA_DISCONNECTED -> DataConnectionState.Disconnected
         DATA_DISCONNECTING -> DataConnectionState.Disconnecting
-        else -> throw IllegalArgumentException("unknown data state received")
+        DATA_UNKNOWN -> DataConnectionState.Unknown
+        else -> throw IllegalArgumentException("unknown data state received $this")
     }
diff --git a/packages/SystemUI/tests/src/com/android/systemui/statusbar/pipeline/mobile/data/repository/MobileConnectionRepositoryTest.kt b/packages/SystemUI/tests/src/com/android/systemui/statusbar/pipeline/mobile/data/repository/MobileConnectionRepositoryTest.kt
index 5ce51bb62c78e..aa7ab0df2ea3d 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/statusbar/pipeline/mobile/data/repository/MobileConnectionRepositoryTest.kt
+++ b/packages/SystemUI/tests/src/com/android/systemui/statusbar/pipeline/mobile/data/repository/MobileConnectionRepositoryTest.kt
@@ -31,6 +31,7 @@ import android.telephony.TelephonyManager.DATA_CONNECTED
 import android.telephony.TelephonyManager.DATA_CONNECTING
 import android.telephony.TelephonyManager.DATA_DISCONNECTED
 import android.telephony.TelephonyManager.DATA_DISCONNECTING
+import android.telephony.TelephonyManager.DATA_UNKNOWN
 import android.telephony.TelephonyManager.NETWORK_TYPE_LTE
 import android.telephony.TelephonyManager.NETWORK_TYPE_UNKNOWN
 import androidx.test.filters.SmallTest
@@ -220,6 +221,21 @@ class MobileConnectionRepositoryTest : SysuiTestCase() {
             job.cancel()
         }
 
+    @Test
+    fun testFlowForSubId_dataConnectionState_unknown() =
+        runBlocking(IMMEDIATE) {
+            var latest: MobileSubscriptionModel? = null
+            val job = underTest.subscriptionModelFlow.onEach { latest = it }.launchIn(this)
+
+            val callback =
+                getTelephonyCallbackForType<TelephonyCallback.DataConnectionStateListener>()
+            callback.onDataConnectionStateChanged(DATA_UNKNOWN, 200 /* unused */)
+
+            assertThat(latest?.dataConnectionState).isEqualTo(DataConnectionState.Unknown)
+
+            job.cancel()
+        }
+
     @Test
     fun testFlowForSubId_dataActivity() =
         runBlocking(IMMEDIATE) {