diff --git a/cura/PrinterOutputDevice.py b/cura/PrinterOutputDevice.py
index 7b79ad4aa4..7bf992ea83 100644
--- a/cura/PrinterOutputDevice.py
+++ b/cura/PrinterOutputDevice.py
@@ -306,4 +306,6 @@ class PrinterOutputDevice(OutputDevice, QObject):
 class ConnectionState(IntEnum):
     closed = 0
     connecting = 1
-    connected = 2
\ No newline at end of file
+    connected = 2
+    busy = 3
+    error = 4
\ No newline at end of file