diff --git a/application.c b/application.c
index 9fe5ae4..8e5d693 100644
--- a/application.c
+++ b/application.c
@@ -271,8 +271,13 @@ static void command_voltages(void* argument)
 static void command_types(void* argument)
 {
 	(void)argument; // we won't use the argument
-	float* voltages;
 	print_target(); // print target voltage (also sets measurement conditions)
+	float* voltages = measure_voltages(); // measure voltages
+	if (voltages[1] < 0.5) { // check target voltage connection
+		puts("connect target voltage to test channel type\n");
+		return;
+	}
+
 	puts("signal voltage  pulled  pull-up pulled pull-down signal\n");
 	puts(" name  raw (V) down (V) (kOhm)  up (V)  (kOhm)    type \n");