diff --git a/heart_rate_sensor_protocol.h b/heart_rate_sensor_protocol.h
index 9128e05..3ae76ee 100644
--- a/heart_rate_sensor_protocol.h
+++ b/heart_rate_sensor_protocol.h
@@ -117,6 +117,8 @@ typedef enum {
   ify_hrs_report_sensor_drop_detect = 105,
   ify_hrs_report_record_upload_end  = 106,
 
+  ify_hrs_cmd_set_ecg_in_test_mode = 150,
+
   ify_hrs_ads1291_wakeup                = 200,
   ify_hrs_ads1291_standby               = 201,
   ify_hrs_ads1291_reset                 = 202,