diff --git a/meshtastic/module_config.proto b/meshtastic/module_config.proto
index 02a5e8a..12c04f6 100644
--- a/meshtastic/module_config.proto
+++ b/meshtastic/module_config.proto
@@ -177,6 +177,8 @@ message ModuleConfig {
       PROTO = 2;
       TEXTMSG = 3;
       NMEA = 4;
+      // NMEA messages specifically tailored for CalTopo
+      CALTOPO = 5;
     }
 
     /*
@@ -591,4 +593,4 @@ enum RemoteHardwarePinType {
    * GPIO pin can be written to (high / low)
    */
   DIGITAL_WRITE = 2;
-}
+}
\ No newline at end of file