diff --git a/lambda-test/alert-test.c b/lambda-test/alert-test.c
index 8d9c29b..5abdbd1 100644
--- a/lambda-test/alert-test.c
+++ b/lambda-test/alert-test.c
@@ -21,14 +21,15 @@
 	beepCount = 0;
 	oscCount = 0;
 
-	// alert with two beep2 with a length of 2
-	alert(2, 2, "a", "b");
+	// alert with two beep2 with a length of 2 and tone 31
+	alert(2, 2, 31, "a", "b");
 	oscillateBeep();
 	oscillateBeep();
 
 	// beep on, alertActive true
 	assertTrue(beepCount == 2);
 	assertTrue(oscCount == 2);
+	assertTrue(OCR1A = 31);
 	assertTrue(bit_is_set(TCCR1A, COM1A0));
 	assertTrue(isAlertActive());
 
@@ -71,11 +72,12 @@
 	beepLength = 0;
 	oscCount = 0;
 
-	beep(1, 2);
+	beep(1, 2, 31);
 
 	assertTrue(beepCount == 1);
 	assertTrue(beepLength == 2);
 	assertTrue(oscCount == 0);
+	assertTrue(OCR1A = 31);
 
 	return true;
 }
@@ -89,11 +91,12 @@
 	beepLength = 0;
 	oscCount = 0;
 
-	alert(1, 2, "a", "b");
+	alert(1, 2, 31, "a", "b");
 
 	assertTrue(beepCount == 1);
 	assertTrue(beepLength == 2);
 	assertTrue(oscCount == 0);
+	assertTrue(OCR1A = 31);
 	assertTrue(isAlertActive());
 
 	return true;
@@ -108,11 +111,12 @@
 	beepLength = 0;
 	oscCount = 0;
 
-	alert(1, 2, "a", "b");
+	alert(1, 2, 31, "a", "b");
 
 	assertTrue(beepCount == 1);
 	assertTrue(beepLength == 2);
 	assertTrue(oscCount == 0);
+	assertTrue(OCR1A = 31);
 	assertTrue(isAlertActive());
 
 	cancelAlert();
diff --git a/lambda-test/display-test.c b/lambda-test/display-test.c
index bc5b104..b413f3f 100644
--- a/lambda-test/display-test.c
+++ b/lambda-test/display-test.c
@@ -45,7 +45,7 @@
 
 	updatePending = false;
 
-	alert(1, 1, "", "");
+	alert(1, 1, 31, "", "");
 	assertTrue(isAlertActive());
 
 	cycleDisplay();
@@ -126,7 +126,7 @@
 	extern bool updatePending;
 
 	updatePending = true;
-	alert(1, 1, "", "");
+	alert(1, 1, 31, "", "");
 	assertTrue(isAlertActive());
 
 	// update should be skipped if alert is active
diff --git a/lambda/alert.c b/lambda/alert.c
index 53d1264..2beb6cd 100644
--- a/lambda/alert.c
+++ b/lambda/alert.c
@@ -11,6 +11,7 @@
 #include <stdio.h>
 #include <stdbool.h>
 #include <avr/io.h>
+#include "integers.h"
 #include "alert.h"
 #include "sensors.h"
 #include "display.h"
@@ -41,14 +42,18 @@
 	oscCount == beepLength * 2 - 1 ? oscCount = 0 : oscCount++;
 }
 
-void beep(uint8_t const beeps, uint8_t const length) {
+void beep(uint8_t const beeps, uint8_t const length, uint16_t const tone) {
+	TCNT1 = 0;
+	OCR1A = tone;
 	oscCount = 0;
 	beepCount = beeps;
 	beepLength = length;
 }
 
-void alert(uint8_t const beeps, uint8_t const length,
+void alert(uint8_t const beeps, uint8_t const length, uint16_t tone,
 		char* const line0, char* const line1) {
+	TCNT1 = 0;
+	OCR1A = tone;
 	alertActive = true;
 	oscCount = 0;
 	beepCount = beeps;
diff --git a/lambda/alert.h b/lambda/alert.h
index e6328e3..0bc8b61 100644
--- a/lambda/alert.h
+++ b/lambda/alert.h
@@ -14,16 +14,18 @@
 void oscillateBeep(void);
 
 /**
- * Beeps the given number of beeps with the given length. Returns quickly so
- * it can be called from an ISR.
+ * Beeps the given number of beeps with the given length and tone.
+ * Returns quickly so it can be called from an ISR.
  */
-void beep(uint8_t beeps, uint8_t length);
+void beep(uint8_t beeps, uint8_t length, uint16_t tone);
 
 /**
- * Beeps the given number of beeps with the given length and displays the
- * given two texts on the first and second line of the display, respectively.
+ * Beeps the given number of beeps with the given length and tone and displays
+ * the given two texts on the first and second line of the display,
+ * respectively.
  */
-void alert(uint8_t beeps, uint8_t length, char* line0, char* line1);
+void alert(uint8_t beeps, uint8_t length, uint16_t tone,
+		char* line0, char* line1);
 
 /**
  * Stops beeping and blocking display updates.
diff --git a/lambda/command.c b/lambda/command.c
index 43704c7..d463ee4 100644
--- a/lambda/command.c
+++ b/lambda/command.c
@@ -39,23 +39,23 @@
 		// simulation enable
 		resetMeas();
 		simulation = true;
-		beep(1, 2);
+		beep(1, 2, 31);
 	}
 	else if (strcmp_P(fields[0], PSTR("sd")) == 0) {
 		// simulation disable
 		resetMeas();
 		simulation = false;
-		beep(1, 2);
+		beep(1, 2, 31);
 	}
 	else if (strcmp_P(fields[0], PSTR("le")) == 0) {
 		// logging enable
 		logging = true;
-		beep(1, 2);
+		beep(1, 2, 31);
 	}
 	else if (strcmp_P(fields[0], PSTR("ld")) == 0) {
 		// logging disable
 		logging = false;
-		beep(1, 2);
+		beep(1, 2, 31);
 	}
 	else if (strcmp_P(fields[0], PSTR("cm")) == 0) {
 		// cycle menu
@@ -65,7 +65,19 @@
 		// test alert
 		char buf[16];
 		strcpy_P(buf, PSTR("Beep Beep Beep!"));
-		alert(3, 10, buf, fields[1]);
+		alert(3, 10, 15, buf, fields[1]);
+	}
+	else if (strcmp_P(fields[0], PSTR("tb")) == 0) {
+		// test beep
+		uint8_t length = 2;
+		if (fields[1] != '\0') {
+			length = atoi(fields[1]);
+		}
+		uint16_t tone = 31;
+		if (fields[2] != '\0') {
+			tone = atoi(fields[2]);
+		}
+		beep(1, length, tone);
 	}
 	else if (simulation) {
 		Measurement meas = readMeas(fields, fieldCount);
diff --git a/lambda/display.c b/lambda/display.c
index c35219a..60a39f6 100644
--- a/lambda/display.c
+++ b/lambda/display.c
@@ -57,7 +57,7 @@
 	if (position > MENU_MAX_VALUES) {
 		position = MENU_OFF;
 	}
-	beep(1, 2);
+	beep(1, 2, 31);
 }
 
 void updateMeas(Measurement const meas) {
diff --git a/lambda/lambda.c b/lambda/lambda.c
index 1cfac6d..b03a8d1 100644
--- a/lambda/lambda.c
+++ b/lambda/lambda.c
@@ -44,7 +44,7 @@
 	initInterrupts();
 	initTimers();
 
-	alert(1, 2, "     Hello!     ", "");
+	alert(1, 2, 31, "     Hello!     ", "");
 
 	Measurement meas;