diff --git a/core/envisalink.py b/core/envisalink.py
index cf6083c..420386c 100644
--- a/core/envisalink.py
+++ b/core/envisalink.py
@@ -1,4 +1,4 @@
-import time, datetime, sys
+import time, datetime, sys, re
 from tornado import gen
 from tornado.tcpclient import TCPClient
 from tornado.iostream import IOStream, StreamClosedError
@@ -98,36 +98,60 @@ def send_command(self, code, data, checksum = True):
             pass
 
     @gen.coroutine
-    def handle_line(self, input):
-        if input != '':
-            if config.ENVISALINKLOGRAW == True:
-                logger.debug('RX RAW < "' + str(input).strip() + '"')
+    def handle_line(self, rawinput):
+        if rawinput == '':
+            return
+
+        input = rawinput.strip()
+        if config.ENVISALINKLOGRAW == True:
+            logger.debug('RX RAW < "' + str(input) + '"')
+
+        if re.match(r'^\d\d:\d\d:\d\d ',input):
+            evltime = input[:8]
+            input = input[9:]
 
-            code=int(input[:3])
-            parameters=input[3:][:-4]
+        if not re.match(r'^[0-9a-fA-F]{5,}$', input):
+            logger.warning('Received invalid TPI message: ' + repr(rawinput));
+            return
+
+        code = int(input[:3])
+        parameters = input[3:][:-2]
+        try:
             event = getMessageType(int(code))
-            message = self.format_event(event, parameters)
-            logger.debug('RX < ' +str(code)+' - '+message)
+        except KeyError:
+            logger.warning('Received unknown TPI code: "%s", parameters: "%s"' %
+                           (input[:3], parameters))
+            return
 
-            try:
-                handler = "handle_%s" % evl_ResponseTypes[code]['handler']
-            except KeyError:
-                handler = "handle_event"
+        rcksum = int(input[-2:], 16)
+        ccksum = int(get_checksum(input[:3],parameters), 16)
+        if rcksum != ccksum:
+            logger.warning('Received invalid TPI checksum %02X vs %02X: "%s"' %
+                           (rcksum, ccksum, input))
+            return
 
-            try:
-                func = getattr(self, handler)
-                if handler != 'handle_login':
-                    events.put('proxy', None, input)
-            except AttributeError:
-                raise CodeError("Handler function doesn't exist")
+        message = self.format_event(event, parameters)
+        logger.debug('RX < ' +str(code)+' - '+message)
 
-            func(code, parameters, event, message)
-            try:
-                line = yield self._connection.read_until(self._terminator)
-                self.handle_line(line)
-            except StreamClosedError:
-                #we don't need to handle this, the callback has been set for closed connections.
-                pass
+        try:
+            handler = "handle_%s" % event['handler']
+        except KeyError:
+            handler = "handle_event"
+
+        try:
+            func = getattr(self, handler)
+            if handler != 'handle_login':
+                events.put('proxy', None, rawinput)
+        except AttributeError:
+            raise CodeError("Handler function doesn't exist")
+
+        func(code, parameters, event, message)
+        try:
+            line = yield self._connection.read_until(self._terminator)
+            self.handle_line(line)
+        except StreamClosedError:
+            #we don't need to handle this, the callback has been set for closed connections.
+            pass
 
     def format_event(self, event, parameters):
         if 'type' in event: