diff --git a/examples/bmon/gen.xml b/examples/bmon/gen.xml
index ba3c360..1cc37f4 100644
--- a/examples/bmon/gen.xml
+++ b/examples/bmon/gen.xml
@@ -4,7 +4,7 @@
         <makefile />
 
         <!-- Tell the generator that this channel maps to a float: -->
-        <channel name="batteryInfo" type="float" />
+        <!--<channel name="batteryInfo" type="float" />-->
     </cpp>
     <cpp variant="ros">
         <catkin>
@@ -23,8 +23,8 @@
         <include src="battery_monitor/InputAccepted.h" />
 
         <!-- Tell the generator that this channel maps non-trivially to a ROS type: -->
-        <channel name="batteryInfo" type="sensor_msgs::BatteryState" topic="/fcs/battery_state" />
-        <channel name="batteryStatus" type="battery_monitor::BatteryStatus" topic="/battery_monitor/battery_status" />
+        <channel name="batteryInfo.in" type="sensor_msgs::BatteryState" topic="/fcs/battery_state" />
+        <channel name="batteryStatus.out" type="battery_monitor::BatteryStatus" topic="/battery_monitor/battery_status" />
         <channel name="inputAccepted" type="battery_monitor::InputAccepted" topic="/battery_monitor/input_accepted" />
 
     </cpp>
diff --git a/internal/gen/config/cpp/context.go b/internal/gen/config/cpp/context.go
index ad95263..47a468a 100644
--- a/internal/gen/config/cpp/context.go
+++ b/internal/gen/config/cpp/context.go
@@ -3,6 +3,7 @@ package cpp
 import (
 	"github.com/UoY-RoboStar/rtcg/internal/stm"
 	"github.com/UoY-RoboStar/rtcg/internal/testlang/rstype"
+	"github.com/UoY-RoboStar/rtcg/internal/testlang/channel"
 )
 
 // Context contains any context derived from the C++ generator config.
@@ -10,9 +11,11 @@ import (
 // This is common to multiple different generators that consider C++ config.
 type Context struct {
 	Includes      []Include              // Includes contains the user-configured includes.
+	Channels 	  []channel.Channel 	 // All channels
 	ChannelTypes  map[string]ChannelType // ChannelTypes contains the calculated channel types.
 	HasConversion bool                   // HasConversion is true if there is a convert.cpp file.
 	ChannelTopics map[string]string		 // Mapping from channel name to topic.
+	// ChannelIO 	  map[string]			 // Indicates whether a channel is input or output.
 }
 
 // Process processes a config into a Context.
@@ -20,9 +23,11 @@ type Context struct {
 func (c *Config) Process(types stm.TypeMap) Context {
 	ctx := Context{
 		Includes:      c.Includes,
+		Channels: 	   c.getChannels(),
 		ChannelTypes:  make(map[string]ChannelType, len(types)),
 		ChannelTopics: c.ChannelTopicMap(),
 		HasConversion: false,
+//		ChannelIO: c.ChannelIO(),
 	}
 
 	overrides := c.ChannelMap()
@@ -50,3 +55,11 @@ type ChannelType struct {
 func (t ChannelType) HasOverride() bool {
 	return t.Override != ""
 }
+
+// // ChannelIO defines whether a channel is input or output
+// type ChannelIO uint8
+
+// const (
+// 	input ChannelIO = iota
+// 	utput ChannelIO = iota
+// )
\ No newline at end of file
diff --git a/internal/gen/config/cpp/cpp.go b/internal/gen/config/cpp/cpp.go
index 0fb5ae4..ec4f541 100644
--- a/internal/gen/config/cpp/cpp.go
+++ b/internal/gen/config/cpp/cpp.go
@@ -4,6 +4,7 @@ package cpp
 import (
 	"github.com/UoY-RoboStar/rtcg/internal/gen/config/catkin"
 	"github.com/UoY-RoboStar/rtcg/internal/gen/config/makefile"
+	"github.com/UoY-RoboStar/rtcg/internal/testlang/channel"
 )
 
 // Config contains configuration for a C++ generator.
@@ -41,12 +42,35 @@ func WithChannel(name, ty string) Option {
 	}
 }
 
+func (c *Config) getChannels() []channel.Channel {
+
+	//carray := make([]channel.Channel, len(c.Channels))
+	var carray []channel.Channel
+
+	for _, chi := range c.Channels {
+		ach := new(channel.Channel)
+		err := ach.UnmarshalText([]byte(chi.Name))
+		if (err == nil) {
+			carray = append(carray, *ach)
+		}
+	}
+
+	return carray
+}
+
 // ChannelMap gets the Channels field of this Config as a map from channel names to type overrides.
 func (c *Config) ChannelMap() map[string]string {
 	cmap := make(map[string]string, len(c.Channels))
 
 	for _, over := range c.Channels {
-		cmap[over.Name] = over.Type
+
+		// Create object and parse
+		chp := new(channel.Channel)
+		err := chp.UnmarshalText([]byte(over.Name))
+
+		if err == nil {
+			cmap[chp.Name] = over.Type
+		}
 	}
 
 	return cmap
@@ -57,12 +81,23 @@ func (c *Config) ChannelTopicMap() map[string]string {
 	cmap := make(map[string]string, len(c.Channels))
 
 	for _, over := range c.Channels {
-		cmap[over.Name] = over.Topic
+
+		// Create object and parse
+		chp := new(channel.Channel)
+		err := chp.UnmarshalText([]byte(over.Name))
+		
+		if err == nil {
+			cmap[chp.Name] = over.Topic
+		} else {
+			cmap[over.Name] = over.Topic
+		}
 	}
 
 	return cmap
 }
 
+// ChannelIO gets the Channel types
+
 
 // Include captures a custom include header.
 type Include struct {
diff --git a/internal/gen/cpp/embed/templates/base/stm.cpp.tmpl b/internal/gen/cpp/embed/templates/base/stm.cpp.tmpl
index 3cbedd5..c152a77 100644
--- a/internal/gen/cpp/embed/templates/base/stm.cpp.tmpl
+++ b/internal/gen/cpp/embed/templates/base/stm.cpp.tmpl
@@ -28,6 +28,9 @@ public:
 {{- range .Transitions.Out }}
   void {{ cppCallbackName .Channel.Name }}(const {{ cppChannelMsgType .Channel.Name }} msg);
 {{- end }}
+{{- range cppOtherOutChannels .Transitions.Out .Channels }}
+  void {{ cppCallbackName .Name }}(const {{ cppChannelMsgType .Name }} msg);
+{{- end }}
 private:
   Verdict verdict_;
   State state_ = {{ (index .Stm.States 0).ID | cppStateEnum }};
@@ -131,6 +134,14 @@ void StateMachine::{{ cppCallbackName .Channel.Name }}(const {{ cppChannelMsgTyp
 }
 {{- end }}
 
+{{- range cppOtherOutChannels .Transitions.Out .Channels }}
+
+void StateMachine::{{ cppCallbackName .Name }}(const {{ cppChannelMsgType .Name }} msg)
+{
+  ROS_INFO_STREAM("Unexpected message for {{ . }}." << std::endl);
+  end(rtcg::Status::OFF_SCRIPT);
+}
+{{- end }}
 
 //
 // State machine entry functions
diff --git a/internal/gen/cpp/embed/templates/ros/main.cpp.tmpl b/internal/gen/cpp/embed/templates/ros/main.cpp.tmpl
index fb6bae6..edba1bb 100644
--- a/internal/gen/cpp/embed/templates/ros/main.cpp.tmpl
+++ b/internal/gen/cpp/embed/templates/ros/main.cpp.tmpl
@@ -64,6 +64,9 @@ const int INPUT_DELAY_SEC = 3;
 {{   range .Transitions.Out }}
   auto {{ template "subscriber_name" . }} = nh.subscribe("{{ cppChannelTopicName $.ChannelTopics .Channel.Name }}", 10, &StateMachine::{{ cppCallbackName .Channel.Name }}, &stm);
 {{-   end }}
+{{- range cppOtherOutChannels .Transitions.Out .Channels }}
+  auto {{ toLowerUnderscored .Name }}_sub = nh.subscribe("{{ cppChannelTopicName $.ChannelTopics .Name }}", 10, &StateMachine::{{ cppCallbackName .Name }}, &stm);
+{{-   end }}
 
   // Timers
   auto timeout_timer = nh.createTimer(ros::Duration(TIMEOUT_SEC), &StateMachine::timeoutCallback, &stm);
diff --git a/internal/gen/cpp/func.go b/internal/gen/cpp/func.go
index ffc2959..9470915 100644
--- a/internal/gen/cpp/func.go
+++ b/internal/gen/cpp/func.go
@@ -5,10 +5,12 @@ import (
 	"strings"
 	"text/template"
 
+	"github.com/UoY-RoboStar/rtcg/internal/stm/transition"
 	"github.com/UoY-RoboStar/rtcg/internal/strmanip"
 	"github.com/UoY-RoboStar/rtcg/internal/testlang"
 	"github.com/UoY-RoboStar/rtcg/internal/testlang/rstype"
 	"github.com/UoY-RoboStar/rtcg/internal/testlang/value"
+	"github.com/UoY-RoboStar/rtcg/internal/testlang/channel"
 )
 
 // Funcs gets the C++ function map.
@@ -18,6 +20,7 @@ func Funcs() template.FuncMap {
 		"cppChannelMsgType":   ChannelMsgType,
 		"cppChannelValueType": ChannelValueType,
 		"cppChannelTopicName": ChannelTopicName,
+		"cppOtherOutChannels": OtherOutChannels,
 		"cppConvertFrom":      ConvertFrom,
 		"cppConvertTo":        ConvertTo,
 		"cppEnumField":        EnumField,
@@ -136,3 +139,27 @@ const (
 	testEnumName    = "Test"    // testEnumName is the name in the C++ code for the test enum.
 	outcomeEnumName = "Outcome" // outcomeEnumName is the name in the C++ code for the outcome enum.
 )
+
+func OtherOutChannels(tagg []transition.AggregateSet, channels []channel.Channel) []channel.Channel {
+
+	var carray []channel.Channel
+
+	for _, c := range channels {
+
+		if (c.IsOut()) {
+			var inside = false
+
+			for _, t := range tagg {
+				if t.Channel == c {
+					inside = true
+				}
+			}
+			
+			if !inside {
+				carray = append(carray, c)
+			}
+		}
+	}
+
+	return carray
+}
\ No newline at end of file