diff --git a/Signal/src/call/CallService.swift b/Signal/src/call/CallService.swift
index 488bd4439..e07ea6540 100644
--- a/Signal/src/call/CallService.swift
+++ b/Signal/src/call/CallService.swift
@@ -470,9 +470,20 @@ protocol CallServiceObserver: class {
 
         let newCall = SignalCall.incomingCall(localId: UUID(), remotePhoneNumber: thread.contactIdentifier(), signalingId: callId)
 
+        guard self.call == nil else {
+            // TODO on iOS10+ we can use CallKit to swap calls rather than just returning busy immediately.
+            Logger.info("\(TAG) receivedCallOffer for thread: \(thread) but we're already in call: \(call!)")
+
+            handleLocalBusyCall(newCall, thread: thread)
+
+            return
+        }
+
         let untrustedIdentity = OWSIdentityManager.shared().untrustedIdentityForSending(toRecipientId: thread.contactIdentifier())
 
         guard untrustedIdentity == nil else {
+            Logger.warn("\(TAG) missed a call due to untrusted identity")
+
             let callerName = self.contactsManager.displayName(forPhoneIdentifier: thread.contactIdentifier())
 
             switch(untrustedIdentity!.verificationState) {
@@ -494,19 +505,15 @@ protocol CallServiceObserver: class {
             newCall.callRecord = callRecord
             callRecord.save()
 
-            return
-        }
-
-        guard self.call == nil else {
-            // TODO on iOS10+ we can use CallKit to swap calls rather than just returning busy immediately.
-            Logger.verbose("\(TAG) receivedCallOffer for thread: \(thread) but we're already in call: \(call!)")
+            terminateCall()
 
-            handleLocalBusyCall(newCall, thread: thread)
             return
         }
 
+        Logger.info("\(TAG) starting new call: \(newCall)")
+
         self.thread = thread
-        call = newCall
+        self.call = newCall
 
         let backgroundTask = UIApplication.shared.beginBackgroundTask {
             let timeout = CallError.timeout(description: "background task time ran out before call connected.")
@@ -808,7 +815,7 @@ protocol CallServiceObserver: class {
         call.callRecord = callRecord
 
         let message = DataChannelMessage.forConnected(callId: call.signalingId)
-        peerConnectionClient.sendDataChannelMessage(data: message.asData())
+        peerConnectionClient.sendDataChannelMessage(data: message.asData(), description:"connected")
 
         handleConnectedCall(call)
     }
@@ -914,7 +921,7 @@ protocol CallServiceObserver: class {
 
         // If the call is connected, we can send the hangup via the data channel.
         let message = DataChannelMessage.forHangup(callId: call.signalingId)
-        peerConnectionClient.sendDataChannelMessage(data: message.asData())
+        peerConnectionClient.sendDataChannelMessage(data: message.asData(), description:"hangup")
 
         // If the call hasn't started yet, we don't have a data channel to communicate the hang up. Use Signal Service Message.
         let hangupMessage = OWSCallHangupMessage(callId: call.signalingId)
@@ -1320,7 +1327,7 @@ protocol CallServiceObserver: class {
         self.peerConnectionClient?.setLocalVideoEnabled(enabled: shouldHaveLocalVideoTrack)
 
         let message = DataChannelMessage.forVideoStreamingStatus(callId: call.signalingId, enabled:shouldHaveLocalVideoTrack)
-        peerConnectionClient.sendDataChannelMessage(data: message.asData())
+        peerConnectionClient.sendDataChannelMessage(data: message.asData(), description:"videoStreamingStatus")
     }
 
     // MARK: - Observers
diff --git a/Signal/src/call/PeerConnectionClient.swift b/Signal/src/call/PeerConnectionClient.swift
index aac1c5098..52f207cac 100644
--- a/Signal/src/call/PeerConnectionClient.swift
+++ b/Signal/src/call/PeerConnectionClient.swift
@@ -505,27 +505,29 @@ class PeerConnectionClient: NSObject, RTCPeerConnectionDelegate, RTCDataChannelD
 
     // MARK: - Data Channel
 
-    public func sendDataChannelMessage(data: Data) {
+    public func sendDataChannelMessage(data: Data, description: String) {
         AssertIsOnMainThread()
 
         PeerConnectionClient.signalingQueue.async {
             guard self.peerConnection != nil else {
-                Logger.debug("\(self.TAG) \(#function) Ignoring obsolete event in terminated client")
+                Logger.debug("\(self.TAG) \(#function) Ignoring obsolete event in terminated client: \(description)")
                 return
             }
 
             guard let dataChannel = self.dataChannel else {
-                Logger.error("\(self.TAG) in \(#function) ignoring sending \(data) for nil dataChannel")
+                Logger.error("\(self.TAG) in \(#function) ignoring sending \(data) for nil dataChannel: \(description)")
                 return
             }
 
+            Logger.debug("\(self.TAG) sendDataChannelMessage trying: \(description)")
+
             let buffer = RTCDataBuffer(data: data, isBinary: false)
             let result = dataChannel.sendData(buffer)
 
             if result {
-                Logger.debug("\(self.TAG) sendDataChannelMessage succeeded")
+                Logger.debug("\(self.TAG) sendDataChannelMessage succeeded: \(description)")
             } else {
-                Logger.warn("\(self.TAG) sendDataChannelMessage failed")
+                Logger.warn("\(self.TAG) sendDataChannelMessage failed: \(description)")
             }
         }
     }