diff --git a/device.h b/device.h
index 0373412..8a518f8 100644
--- a/device.h
+++ b/device.h
@@ -17,10 +17,15 @@
 #endif
 
 // ADC settings
-#define OPEN_SQUELCH false
-#define ADC_REFERENCE REF_3V3
-// OR
-//#define ADC_REFERENCE REF_5V
+#ifndef OPEN_SQUELCH
+    #define OPEN_SQUELCH false
+#endif
+
+#ifndef ADC_REFERENCE
+    #define ADC_REFERENCE REF_3V3
+    // OR
+    //#define ADC_REFERENCE REF_5V
+#endif
 
 // Sampling & timer setup
 #define CONFIG_AFSK_DAC_SAMPLERATE 9600
diff --git a/examples/Basic_usage/Basic_usage.ino b/examples/Basic_usage/Basic_usage.ino
index 3aaae2d..37de64a 100644
--- a/examples/Basic_usage/Basic_usage.ino
+++ b/examples/Basic_usage/Basic_usage.ino
@@ -1,3 +1,17 @@
+// You must define what reference voltage the ADC
+// of your device is running at. If you bought a
+// MicroModem from unsigned.io, it will be running
+// at 3.3v if the "hw rev" is greater than 2.0.
+// This is the most common. If you build your own
+// modem, you should know this value yourself :)
+#define ADC_REFERENCE REF_3V3
+// OR
+//#define ADC_REFERENCE REF_5V
+
+// You can also define whether your modem will be
+// running with an open squelch radio:
+#define OPEN_SQUELCH false
+
 // Include LibAPRS
 #include <LibAPRS.h>