diff --git a/device.h b/device.h
index c26447a..92d3a63 100644
--- a/device.h
+++ b/device.h
@@ -5,7 +5,7 @@
 
 // CPU settings
 #define TARGET_CPU m328p
-#define F_CPU 16000000
+#define F_CPU  8000000
 #define FREQUENCY_CORRECTION 0
 
 // ADC settings
@@ -18,9 +18,9 @@
 #define CONFIG_AFSK_DAC_SAMPLERATE 9600
 
 // Serial protocol settings
-#define SERIAL_PROTOCOL PROTOCOL_KISS
+//#define SERIAL_PROTOCOL PROTOCOL_KISS
 // OR
-//#define SERIAL_PROTOCOL PROTOCOL_SIMPLE_SERIAL
+#define SERIAL_PROTOCOL PROTOCOL_SIMPLE_SERIAL
 
 // AX25 settings
 #if SERIAL_PROTOCOL == PROTOCOL_SIMPLE_SERIAL
@@ -42,4 +42,4 @@
     #define ADC_DDR  DDRC
 #endif
 
-#endif
\ No newline at end of file
+#endif
diff --git a/hardware/AFSK.c b/hardware/AFSK.c
index c8c5f90..799db33 100644
--- a/hardware/AFSK.c
+++ b/hardware/AFSK.c
@@ -495,13 +495,17 @@ void AFSK_adc_isr(Afsk *afsk, int8_t currentSample) {
 }
 
 
+// Set the DAC pins to their output, and clear the PTT pin (which is
+// hardware pin 3 on PORT D) when transmitting.  Set the DAC pins to
+// "zero" (i.e. half of full potential) and set the PTT pin when not
+// transmitting.
 ISR(ADC_vect) {
     TIFR1 = _BV(ICF1);
     AFSK_adc_isr(AFSK_modem, ((int16_t)((ADC) >> 2) - 128));
     if (hw_afsk_dac_isr) {
-        DAC_PORT = (AFSK_dac_isr(AFSK_modem) & 0xF0) | _BV(3); 
+        DAC_PORT = (AFSK_dac_isr(AFSK_modem) & 0xF0) & ~_BV(3); 
     } else {
-        DAC_PORT = 128;
+        DAC_PORT = 128 | _BV(3);
     }
     ++_clock;
-}
\ No newline at end of file
+}
diff --git a/hardware/AFSK.h b/hardware/AFSK.h
index aecce47..74890a2 100644
--- a/hardware/AFSK.h
+++ b/hardware/AFSK.h
@@ -137,23 +137,23 @@ typedef struct Afsk
 
 #define AFSK_DAC_IRQ_START()   do { extern bool hw_afsk_dac_isr; hw_afsk_dac_isr = true; } while (0)
 #define AFSK_DAC_IRQ_STOP()    do { extern bool hw_afsk_dac_isr; hw_afsk_dac_isr = false; } while (0)
-#define AFSK_DAC_INIT()        do { DAC_DDR |= 0xF8; } while (0)
+#define AFSK_DAC_INIT()        do { DAC_DDR |= 0xF8; DAC_PORT |= _BV(3); } while (0)
 
 // Here's some macros for controlling the RX/TX LEDs
 // THE _INIT() functions writes to the DDRB register
 // to configure the pins as output pins, and the _ON()
 // and _OFF() functions writes to the PORT registers
 // to turn the pins on or off.
-#define LED_TX_INIT() do { LED_DDR |= _BV(1); } while (0)
-#define LED_TX_ON()   do { LED_PORT |= _BV(1); } while (0)
-#define LED_TX_OFF()  do { LED_PORT &= ~_BV(1); } while (0)
+#define LED_TX_INIT() do { LED_DDR |= _BV(2); } while (0)
+#define LED_TX_ON()   do { LED_PORT |= _BV(2); } while (0)
+#define LED_TX_OFF()  do { LED_PORT &= ~_BV(2); } while (0)
 
-#define LED_RX_INIT() do { LED_DDR |= _BV(2); } while (0)
-#define LED_RX_ON()   do { LED_PORT |= _BV(2); } while (0)
-#define LED_RX_OFF()  do { LED_PORT &= ~_BV(2); } while (0)
+#define LED_RX_INIT() do { LED_DDR |= _BV(1); } while (0)
+#define LED_RX_ON()   do { LED_PORT |= _BV(1); } while (0)
+#define LED_RX_OFF()  do { LED_PORT &= ~_BV(1); } while (0)
 
 void AFSK_init(Afsk *afsk);
 void AFSK_transmit(char *buffer, size_t size);
 void AFSK_poll(Afsk *afsk);
 
-#endif
\ No newline at end of file
+#endif
diff --git a/main.c b/main.c
index 9ff480b..ff23377 100644
--- a/main.c
+++ b/main.c
@@ -77,6 +77,7 @@ int main (void) {
 
             if (!sertx && serial_available(0)) {
                 sbyte = uart0_getchar_nowait();
+		// uart0_putchar(sbyte);	// echo it back
 
                 #if SERIAL_DEBUG
                     if ((serialLen < AX25_MAX_FRAME_LEN) && (sbyte != 10)) {
@@ -113,4 +114,4 @@ int main (void) {
     #endif
 
     return(0);
-}
\ No newline at end of file
+}