diff --git a/canbus.cpp b/canbus.cpp
index c01f274..91e83ad 100644
--- a/canbus.cpp
+++ b/canbus.cpp
@@ -17,7 +17,7 @@ CANBus::CANBus(const CANBus& pBus) :
     active(pBus.active) {}
 
 
-bool CANBus::operator==(CANBus& bus) {
+bool CANBus::operator==(const CANBus& bus) const{
     return  speed == bus.speed &&
             listenOnly == bus.listenOnly &&
             singleWire == bus.singleWire &&
diff --git a/canbus.h b/canbus.h
index c8b4e88..8dd8044 100644
--- a/canbus.h
+++ b/canbus.h
@@ -7,7 +7,7 @@ class CANBus
 public:
     CANBus();
     CANBus(const CANBus&);
-    bool operator==(CANBus&);
+    bool operator==(const CANBus&) const;
     virtual ~CANBus(){}; /*TODO: remove connection from CANBus and add CANBus as an element of CANConnection */
     int speed;
     bool listenOnly;