diff --git a/cmd/gqgmc/main.go b/cmd/gqgmc/main.go
index 46cb804c7fa84cd1175fb3740c1dc15b5fb4e59d..120606da69697929d010bfdcc65ebe79fbcf22e5 100644
--- a/cmd/gqgmc/main.go
+++ b/cmd/gqgmc/main.go
@@ -57,13 +57,13 @@ func main() {
 		fmt.Printf("Failed to connect to geiger counter: '%s'\n", err)
 		return
 	}
-	fmt.Printf("Version: %s\n", ser)
+	fmt.Printf("Serial: %s\n", ser)
 
 	volts, err = gc.Volts()
 	if err != nil {
 		fmt.Printf("Failed to connect to geiger counter: '%s'\n", err)
 		return
 	}
-	fmt.Printf("Version: %d\n", volts)
+	fmt.Printf("Volts: %d\n", volts)
 
 }
diff --git a/devices/geiger/gqgmc.go b/devices/geiger/gqgmc.go
index e028a77d1ec3c44c29843922e6dbc4faaa243b90..7bd8db4b7ab450fd2bd426774df29b451c5efc2d 100644
--- a/devices/geiger/gqgmc.go
+++ b/devices/geiger/gqgmc.go
@@ -155,7 +155,7 @@ func (gc *GQGMCCounter) SerialNum() (string, error) {
 	serStr := ""
 
 	ser, err := gc.communicate(cmdGetSerial, 7)
-	if err != nil {
+	if err == nil {
 		for _, b := range ser {
 			serStr += fmt.Sprintf("%02X", b)
 		}