diff --git a/Modem/main.c b/Modem/main.c
index 2759796..51b368f 100644
--- a/Modem/main.c
+++ b/Modem/main.c
@@ -27,11 +27,6 @@ static Serial ser;			// Declare a serial interface struct
 #define ADC_CH 0			// Define which channel (pin) we want
 							// for the ADC (this is A0 on arduino)
 
-#define TEST_TX false		// Whether we should send test packets
-							// periodically, plus what to send:
-#define TEST_PACKET "Packet received. This is an ACK."
-#define TEST_TX_INTERVAL 10000L
-
 
 static uint8_t serialBuffer[MP1_MAX_DATA_SIZE];	// This is a buffer for incoming serial data
 
@@ -50,13 +45,6 @@ static bool sertx = false;							// Flag signifying whether it's time to send da
 static void mp1Callback(struct MP1Packet *packet) {
 	if (SERIAL_DEBUG) {
 		kfile_printf(&ser.fd, "%.*s\n", packet->dataLength, packet->data);
-
-		if (AUTOREPLY && packet->data[0]-128 == 'R' && packet->data[1]-128 == 'Q') {
-			timer_delay(1000);
-			
-			uint8_t output[sizeof(TEST_PACKET)] = TEST_PACKET;
-			mp1Send(&mp1, output, sizeof(TEST_PACKET));
-		}
 	} else {
 		for (unsigned long i = 0; i < packet->dataLength; i++) {
 			kfile_putc(packet->data[i], &ser.fd);
@@ -174,15 +162,6 @@ int main(void)
 				serialLen = 0;
 			}
 		}
-
-		// Periodically send test data if we should do so
-		if (SERIAL_DEBUG && TEST_TX && timer_clock() - start > ms_to_ticks(TEST_TX_INTERVAL)) {
-			// Reset the timer counter;
-			start = timer_clock();
-			// And send a test packet!
-			uint8_t output[sizeof(TEST_PACKET)] = TEST_PACKET;
-			mp1Send(&mp1, output, sizeof(TEST_PACKET));
-		}
 	}
 	return 0;
 }
\ No newline at end of file
diff --git a/Modem/protocol/mp1.c b/Modem/protocol/mp1.c
index 7883f24..36659c3 100644
--- a/Modem/protocol/mp1.c
+++ b/Modem/protocol/mp1.c
@@ -544,21 +544,25 @@ void mp1Init(MP1 *mp1, KFile *modem, mp1_callback_t callback) {
 // number, and if it is less than
 // MP1_P_PERSISTENCE, we transmit.
 bool mp1CarrierSense(MP1 *mp1) {
-	if (mp1->randomSeed == 0) {
-		mp1->randomSeed = timer_clock();
-		srand(mp1->randomSeed);
-	}
+	if (MP1_ENABLE_CSMA) {
+		if (mp1->randomSeed == 0) {
+			mp1->randomSeed = timer_clock();
+			srand(mp1->randomSeed);
+		}
 
-	if (timer_clock() - mp1->settleTimer > ms_to_ticks(MP1_SETTLE_TIME)) {
-		uint8_t r = rand() % 255;
-		if (r < MP1_P_PERSISTENCE) {
-			return false;
+		if (timer_clock() - mp1->settleTimer > ms_to_ticks(MP1_SETTLE_TIME)) {
+			uint8_t r = rand() % 255;
+			if (r < MP1_P_PERSISTENCE) {
+				return false;
+			} else {
+				mp1->settleTimer = timer_clock();
+				return true;
+			}
 		} else {
-			mp1->settleTimer = timer_clock();
 			return true;
 		}
 	} else {
-		return true;
+		return false;
 	}
 }
 
diff --git a/Modem/protocol/mp1.h b/Modem/protocol/mp1.h
index e46fa5c..7b15a1d 100644
--- a/Modem/protocol/mp1.h
+++ b/Modem/protocol/mp1.h
@@ -16,6 +16,7 @@
 
 // These two parameters are used for 
 // P-persistent CSMA
+#define MP1_ENABLE_CSMA false
 #define MP1_SETTLE_TIME 100UL		// The minimum wait time before considering sending
 #define MP1_P_PERSISTENCE 85UL		// The probability (between 0 and 255) for sending
 #define MP1_TXDELAY 150UL			// Delay between turning on the transmitter and sending
diff --git a/buildrev.h b/buildrev.h
index 7a9c086..d1b1ff9 100644
--- a/buildrev.h
+++ b/buildrev.h
@@ -1,2 +1,2 @@
-#define VERS_BUILD 1570
+#define VERS_BUILD 1576
 #define VERS_HOST  "shard"