diff --git a/src/lib.rs b/src/lib.rs
index db5972f..d77e618 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -717,6 +717,15 @@ impl MessageBehavior for DeviceTranform {
         if msg.args.len() != 8 {
             return Err(String::from("arg count invalid"));
         }
+        match msg.addr.as_str() {
+            "/VMC/Ext/Hmd/Pos"
+            | "/VMC/Ext/Con/Pos"
+            | "/VMC/Ext/Tra/Pos"
+            | "/VMC/Ext/Hmd/Pos/Local"
+            | "/VMC/Ext/Con/Pos/Local"
+            | "/VMC/Ext/Tra/Pos/Local" => {}
+            _ => return Err(String::from("addr invalid")),
+        }
         let serial: String;
         let mut origin = Vector3::new(0.0, 0.0, 0.0);
         let mut quat = Quaternion::new(0.0, 0.0, 0.0, 0.0);
@@ -759,3 +768,69 @@ impl MessageBehavior for DeviceTranform {
         });
     }
 }
+
+struct VmcExtRvc {
+    enable: bool,
+    port: u16,
+    ip_addr: Option<String>,
+}
+
+impl MessageBehavior for VmcExtRvc {
+    fn to_sendable_osc_message(&self) -> OscMessage {
+        let mut args: Vec<OscType>;
+        if self.enable {
+            args = vec![OscType::from(1)];
+        } else {
+            args = vec![OscType::from(0)];
+        }
+        args.push(OscType::from(self.port as i32));
+        if self.ip_addr.is_some() {
+            args.push(OscType::from(self.ip_addr.clone().unwrap()));
+        }
+        return OscMessage {
+            addr: String::from("/VMC/Ext/Rvc"),
+            args,
+        };
+    }
+    fn parse_from_osc_message(msg: OscMessage) -> Result<Self, String> {
+        if msg.args.len() < 2 || msg.args.len() > 3 {
+            return Err(String::from("arg count invalid"));
+        }
+        let enable: bool;
+        let port: u16;
+        let mut ip_addr: Option<String> = None;
+        match msg.args[0] {
+            OscType::Int(i) => {
+                if i == 0 {
+                    enable = false;
+                } else if i == 1 {
+                    enable = true;
+                } else {
+                    return Err(String::from("arg value invalid"));
+                }
+            }
+            _ => return Err(String::from("arg type invalid")),
+        }
+        match msg.args[1] {
+            OscType::Int(i) => {
+                if i >= 0 && i <= 65535 {
+                    port = i as u16;
+                } else {
+                    return Err(String::from("arg value invalid"));
+                }
+            }
+            _ => return Err(String::from("arg type invalid")),
+        }
+        if msg.args.len() == 3 {
+            match &msg.args[2] {
+                OscType::String(s) => ip_addr = Some(s.to_owned()),
+                _ => return Err(String::from("arg type invalid")),
+            }
+        }
+        return Ok(VmcExtRvc {
+            enable,
+            port,
+            ip_addr,
+        });
+    }
+}