diff --git a/TC_types.h b/TC_types.h
--- a/TC_types.h
+++ b/TC_types.h
@@ -88,7 +88,7 @@ typedef struct
     unsigned char set2;
     unsigned char set3_bias_setting_set1[6];
     unsigned char set3_bias_setting_set2[6];
-    unsigned char set3_bias_voltage[4];
+    unsigned char set3_bias_voltage[2];
     unsigned char set4[8];
     unsigned char set5;
     unsigned char set6;