diff --git a/src/atest.c b/src/atest.c
index e395c09..f7e40b3 100644
--- a/src/atest.c
+++ b/src/atest.c
@@ -82,7 +82,7 @@
 #include "ptt.h"
 #include "dtime_now.h"
 #include "fx25.h"
-
+#include "hdlc_rec.h"
 
 
 #if 0	/* Typical but not flexible enough. */
@@ -188,6 +188,9 @@ static int J_opt = 0;			/* 2400 bps PSK compatible MFJ-2400 and maybe others. */
 static int h_opt = 0;			// Hexadecimal display of received packet.
 static char P_opt[16] = "";		// Demodulator profiles.
 static int d_x_opt = 1;			// FX.25 debug.
+static int d_o_opt = 0;			// "-d o" option for DCD output control. */	
+static int dcd_count = 0;
+static int dcd_missing_errors = 0;
 
 
 int main (int argc, char *argv[])
@@ -382,6 +385,7 @@ int main (int argc, char *argv[])
 	       for (char *p=optarg; *p!='\0'; p++) {
 	        switch (*p) {
 	           case 'x':  d_x_opt++; break;			// FX.25
+	           case 'o':  d_o_opt++; break;			// DCD output control
 	           default: break;
 	        }
 	       }
@@ -686,6 +690,10 @@ int main (int argc, char *argv[])
 	elapsed = dtime_now() - start_time;
 
 	dw_printf ("%d packets decoded in %.3f seconds.  %.1f x realtime\n", packets_decoded_total, elapsed, total_filetime/elapsed);
+	if (d_o_opt) {
+	  dw_printf ("DCD count = %d\n", dcd_count);
+	  dw_printf ("DCD missing erors = %d\n", dcd_missing_errors);
+	}
 
 	if (error_if_less_than != -1 && packets_decoded_total < error_if_less_than) {
 	  text_color_set(DW_COLOR_ERROR);
@@ -744,6 +752,7 @@ void dlq_rec_frame (int chan, int subchan, int slice, packet_t pp, alevel_t alev
 	char alevel_text[AX25_ALEVEL_TO_TEXT_SIZE];
 
 	packets_decoded_one++;
+	if ( ! hdlc_rec_data_detect_any(chan)) dcd_missing_errors++;
 
 	ax25_format_addrs (pp, stemp);
 
@@ -777,7 +786,7 @@ void dlq_rec_frame (int chan, int subchan, int slice, packet_t pp, alevel_t alev
 	int min = (int)(sec / 60.);
 	sec -= min * 60;
 
-	dw_printf ("%d:%07.4f ", min, sec);
+	dw_printf ("%d:%06.3f ", min, sec);
 
 	if (h != AX25_SOURCE) {
 	  dw_printf ("Digipeater ");
@@ -876,6 +885,38 @@ void dlq_rec_frame (int chan, int subchan, int slice, packet_t pp, alevel_t alev
 
 void ptt_set (int ot, int chan, int ptt_signal)
 {
+	// Should only get here for DCD output control.
+	static double dcd_start_time[MAX_CHANS];
+
+	if (d_o_opt) {
+	  double t = (double)sample_number / my_audio_config.adev[0].samples_per_sec;
+	  double sec1, sec2;
+	  int min1, min2;
+
+	  text_color_set(DW_COLOR_INFO);
+
+	  if (ptt_signal) {
+	    //sec1 = t;
+	    //min1 = (int)(sec1 / 60.);
+	    //sec1 -= min1 * 60;
+	    //dw_printf ("DCD[%d] = ON    %d:%06.3f\n",  chan, min1, sec1);
+	    dcd_count++;
+	    dcd_start_time[chan] = t;
+	  }
+	  else {
+	    //dw_printf ("DCD[%d] = off   %d:%06.3f   %3.0f\n",  chan, min, sec, (t - dcd_start_time[chan]) * 1000.);
+
+	    sec1 = dcd_start_time[chan];
+	    min1 = (int)(sec1 / 60.);
+	    sec1 -= min1 * 60;
+
+	    sec2 = t;
+	    min2 = (int)(sec2 / 60.);
+	    sec2 -= min2 * 60;
+
+	    dw_printf ("DCD[%d]  %d:%06.3f - %d:%06.3f =  %3.0f\n",  chan, min1, sec1, min2, sec2, (t - dcd_start_time[chan]) * 1000.);
+	  }
+	}
 	return;
 }
 
diff --git a/src/demod_9600.c b/src/demod_9600.c
index a0e1ff0..2f98983 100644
--- a/src/demod_9600.c
+++ b/src/demod_9600.c
@@ -44,14 +44,24 @@
 #include <assert.h>
 #include <ctype.h>
 
+// Fine tuning for different demodulator types.
+
+#define DCD_THRESH_ON 32		// Hysteresis: Can miss 0 out of 32 for detecting lock.
+					// This is best for actual on-the-air signals.
+					// Still too many brief false matches.
+#define DCD_THRESH_OFF 8		// Might want a little more fine tuning.
+#define DCD_GOOD_WIDTH 1024		// No more than 1024!!!
+#include "fsk_demod_state.h"		// Values above override defaults.
+
 #include "tune.h"
-#include "fsk_demod_state.h"
 #include "hdlc_rec.h"
 #include "demod_9600.h"
 #include "textcolor.h"
 #include "dsp.h"
 
 
+
+
 static float slice_point[MAX_SUBCHANS];
 
 
@@ -407,7 +417,7 @@ void demod_9600_process_sample (int chan, int sam, struct demodulator_state_s *D
 	if (chan == 0) {
 
 	  if (1) {
-	  //if (hdlc_rec_gathering (chan, subchan, slice)) {
+	  //if (D->slicer[slice].data_detect) {
 	    char fname[30];
 	    int slice = 0;
 
@@ -516,6 +526,7 @@ inline static void nudge_pll (int chan, int subchan, int slice, float demod_out_
 	  /* Overflow.  Was large positive, wrapped around, now large negative. */
 
 	  hdlc_rec_bit (chan, subchan, slice, demod_out_f > 0, D->modem_type == MODEM_SCRAMBLE, D->slicer[slice].lfsr);
+	  pll_dcd_each_symbol2 (D, chan, subchan, slice);
 	}
 
 /*
@@ -526,11 +537,11 @@ inline static void nudge_pll (int chan, int subchan, int slice, float demod_out_
 
 	  // Note:  Test for this demodulator, not overall for channel.
 
-	  float target = 0;
+	  pll_dcd_signal_transition2 (D, slice, D->slicer[slice].data_clock_pll);
 
-	  target = D->pll_step_per_sample * demod_out_f / (demod_out_f - D->slicer[slice].prev_demod_out_f);
+	  float target = D->pll_step_per_sample * demod_out_f / (demod_out_f - D->slicer[slice].prev_demod_out_f);
 
-	  if (hdlc_rec_gathering (chan, subchan, slice)) {
+	  if (D->slicer[slice].data_detect) {
 	    D->slicer[slice].data_clock_pll = (int)(D->slicer[slice].data_clock_pll * D->pll_locked_inertia + target * (1.0f - D->pll_locked_inertia) );
 	  }
 	  else {
@@ -542,7 +553,7 @@ inline static void nudge_pll (int chan, int subchan, int slice, float demod_out_
 #if DEBUG5
 
 	//if (chan == 0) {
-	if (hdlc_rec_gathering (chan,subchan,slice)) {
+	if (D->slicer[slice].data_detect) {
 	
 	  char fname[30];
 
diff --git a/src/demod_afsk.c b/src/demod_afsk.c
index 7d47aa0..76defd0 100644
--- a/src/demod_afsk.c
+++ b/src/demod_afsk.c
@@ -762,7 +762,7 @@ void demod_afsk_process_sample (int chan, int subchan, int sam, struct demodulat
 #if DEBUG4
 
 	if (chan == 0) {
-	if (hdlc_rec_gathering (chan, subchan)) {
+	if (D->slicer[slice].data_detect) {
 	  char fname[30];
 
 	  
@@ -839,16 +839,18 @@ inline static void nudge_pll (int chan, int subchan, int slice, int demod_data,
 
 	if (D->slicer[slice].data_clock_pll < 0 && D->slicer[slice].prev_d_c_pll > 0) {
 
-	  /* Overflow. */
+	  /* Overflow - this is where we sample. */
 	  hdlc_rec_bit (chan, subchan, slice, demod_data, 0, -1);
+	  pll_dcd_each_symbol2 (D, chan, subchan, slice);
 	}
 
-	// Even if we used alternative method to extract the data bit,
-	//  we still use the low pass output for the PLL.
+	// Transitions nudge the DPLL phase toward the incoming signal.
 
         if (demod_data != D->slicer[slice].prev_demod_data) {
 
-	  if (hdlc_rec_gathering (chan, subchan, slice)) {
+	  pll_dcd_signal_transition2 (D, slice, D->slicer[slice].data_clock_pll);
+
+	  if (D->slicer[slice].data_detect) {
 	    D->slicer[slice].data_clock_pll = (int)(D->slicer[slice].data_clock_pll * D->pll_locked_inertia);
 	  }
 	  else {
diff --git a/src/demod_psk.c b/src/demod_psk.c
index a1565e9..017c640 100644
--- a/src/demod_psk.c
+++ b/src/demod_psk.c
@@ -86,16 +86,25 @@
 #include <assert.h>
 #include <ctype.h>
 
+// Fine tuning for different demodulator types.
+
+#define DCD_THRESH_ON 30		// Hysteresis: Can miss 2 out of 32 for detecting lock.
+#define DCD_THRESH_OFF 6		// Might want a little more fine tuning.
+#define DCD_GOOD_WIDTH 512
+#include "fsk_demod_state.h"		// Values above override defaults.
 
 #include "audio.h"
 #include "tune.h"
-#include "fsk_demod_state.h"
 #include "fsk_gen_filter.h"
 #include "hdlc_rec.h"
 #include "textcolor.h"
 #include "demod_psk.h"
 #include "dsp.h"
 
+
+
+
+
 static const int phase_to_gray_v26[4] = {0, 1, 3, 2};	
 static const int phase_to_gray_v27[8] = {1, 0, 2, 3, 7, 6, 4, 5};	
 
@@ -800,6 +809,7 @@ static void nudge_pll (int chan, int subchan, int slice, int demod_bits, struct
 	    hdlc_rec_bit (chan, subchan, slice, (gray >> 1) & 1, 0, bit_quality[1]);
 	    hdlc_rec_bit (chan, subchan, slice, gray & 1, 0, bit_quality[0]);
 	  }
+	  pll_dcd_each_symbol2 (D, chan, subchan, slice);
 	}
 
 /*
@@ -813,7 +823,9 @@ static void nudge_pll (int chan, int subchan, int slice, int demod_bits, struct
 
         if (demod_bits != D->slicer[slice].prev_demod_data) {
 
-	  if (hdlc_rec_gathering (chan, subchan, slice)) {
+	  pll_dcd_signal_transition2 (D, slice, D->slicer[slice].data_clock_pll);
+
+	  if (D->slicer[slice].data_detect) {
 	    D->slicer[slice].data_clock_pll = (int)floorf((float)(D->slicer[slice].data_clock_pll) * D->pll_locked_inertia);
 	  }
 	  else {
diff --git a/src/fsk_demod_state.h b/src/fsk_demod_state.h
index a12c1e5..f7b5650 100644
--- a/src/fsk_demod_state.h
+++ b/src/fsk_demod_state.h
@@ -226,6 +226,8 @@ struct demodulator_state_s
 		signed int data_clock_pll;		// PLL for data clock recovery.
 							// It is incremented by pll_step_per_sample
 							// for each audio sample.
+							// Must be 32 bits!!!
+							// So far, this is the case for every compiler used.
 
 		signed int prev_d_c_pll;		// Previous value of above, before
 							// incrementing, to detect overflows.
@@ -238,6 +240,18 @@ struct demodulator_state_s
 
 		int lfsr;				// Descrambler shift register.
 
+		// This is for detecting phase lock to incoming signal.
+
+		int good_flag;				// Set if transition is near where expected,
+							// i.e. at a good time.
+		int bad_flag;				// Set if transition is not where expected,
+							// i.e. at a bad time.
+		unsigned char good_hist;		// History of good transitions for past octet.
+		unsigned char bad_hist;			// History of bad transitions for past octet.
+		unsigned int score;			// History of whether good triumphs over bad
+							// for past 32 symbols.
+		int data_detect;			// True when locked on to signal.
+		
 	} slicer [MAX_SLICERS];				// Actual number in use is num_slicers.
 							// Should be in range 1 .. MAX_SLICERS,
 /*
@@ -336,5 +350,100 @@ struct demodulator_state_s
 
 };
 
+
+/*-------------------------------------------------------------------
+ *
+ * Name:        pll_dcd_signal_transition2
+ *		dcd_each_symbol2
+ *
+ * Purpose:     New DCD strategy for 1.6.
+ *
+ * Inputs:	D		Pointer to demodulator state.
+ *
+ *		chan		Radio channel: 0 to MAX_CHANS - 1	
+ *
+ *		subchan		Which of multiple demodulators: 0 to MAX_SUBCHANS - 1
+ *
+ *		slice		Slicer number: 0 to MAX_SLICERS - 1.
+ *
+ *		dpll_phase	Signed 32 bit counter for DPLL phase.
+ *				Wraparound is where data is sampled.
+ *				Ideally transitions would occur close to 0.
+ *				
+ * Output:	D->slicer[slice].data_detect - true when PLL is locked to incoming signal.
+ *
+ * Description:	From the beginning, DCD was based on finding several flag octets
+ *		in a row and dropping when eight bits with no transitions.
+ *		It was less than ideal but we limped along with it all these years.
+ *		This fell apart when FX.25 came along and a couple of the
+ *		correlation tags have eight "1" bits in a row.
+ *
+ * 		Our new strategy is to keep a running score of how well demodulator
+ *		output transitions match to where expected.
+ *
+ *--------------------------------------------------------------------*/
+
+#include "hdlc_rec.h"        // for dcd_change
+
+// These are good for 1200 bps AFSK.
+// Might want to override for other modems.
+
+#ifndef DCD_THRESH_ON
+#define DCD_THRESH_ON 30		// Hysteresis: Can miss 2 out of 32 for detecting lock.
+					// 31 is best for TNC Test CD.  30 almost as good.
+					// 30 better for 1200 regression test.
+#endif
+
+#ifndef DCD_THRESH_OFF
+#define DCD_THRESH_OFF 6		// Might want a little more fine tuning.
+#endif
+
+#ifndef DCD_GOOD_WIDTH
+#define DCD_GOOD_WIDTH 512		// No more than 1024!!!
+#endif
+
+__attribute__((always_inline))
+inline static void pll_dcd_signal_transition2 (struct demodulator_state_s *D, int slice, int dpll_phase)
+{
+	if (dpll_phase > - DCD_GOOD_WIDTH * 1024 * 1024 && dpll_phase < DCD_GOOD_WIDTH * 1024 * 1024) {
+	  D->slicer[slice].good_flag = 1;
+	}
+	else {
+	  D->slicer[slice].bad_flag = 1;
+	}
+}
+
+__attribute__((always_inline))
+inline static void pll_dcd_each_symbol2 (struct demodulator_state_s *D, int chan, int subchan, int slice)
+{
+	D->slicer[slice].good_hist <<= 1;
+	D->slicer[slice].good_hist |= D->slicer[slice].good_flag;
+	D->slicer[slice].good_flag = 0;
+
+	D->slicer[slice].bad_hist <<= 1;
+	D->slicer[slice].bad_hist |= D->slicer[slice].bad_flag;
+	D->slicer[slice].bad_flag = 0;
+
+	D->slicer[slice].score <<= 1;
+	// 2 is to detect 'flag' patterns with 2 transitions per octet.
+	D->slicer[slice].score |= (signed)__builtin_popcount(D->slicer[slice].good_hist)
+					- (signed)__builtin_popcount(D->slicer[slice].bad_hist) >= 2;
+
+	int s = __builtin_popcount(D->slicer[slice].score);
+	if (s >= DCD_THRESH_ON) {
+	  if (D->slicer[slice].data_detect == 0) {
+	    D->slicer[slice].data_detect = 1;
+	    dcd_change (chan, subchan, slice, D->slicer[slice].data_detect);
+	  }
+	}
+	else if (s <= DCD_THRESH_OFF) {
+	  if (D->slicer[slice].data_detect != 0) {
+	    D->slicer[slice].data_detect = 0;
+	    dcd_change (chan, subchan, slice, D->slicer[slice].data_detect);
+	  }
+	}
+}
+
+
 #define FSK_DEMOD_STATE_H 1
-#endif
\ No newline at end of file
+#endif
diff --git a/src/gen_packets.c b/src/gen_packets.c
index c05ff22..b097790 100644
--- a/src/gen_packets.c
+++ b/src/gen_packets.c
@@ -117,6 +117,11 @@ static void send_packet (char *str)
 	}
 	else {
 	  pp = ax25_from_text (str, 1);
+	  if (pp == NULL) {
+            text_color_set(DW_COLOR_ERROR);
+            dw_printf ("\"%s\" is not valid TNC2 monitoring format.\n", str);
+	    return;
+	  }
 	  flen = ax25_pack (pp, fbuf);
 	  for (c=0; c<modem.adev[0].num_channels; c++)
 	  {
@@ -124,8 +129,7 @@ static void send_packet (char *str)
 #if 1
 	    int samples_per_symbol, n, j;
 
-/* Insert random amount of quiet time, approx. 0 to 10 symbol times, to test */
-/* how well the clock recovery PLL can regain lock after random phase shifts. */
+	    // Insert random amount of quiet time.
 
 	    if (modem.achan[c].modem_type == MODEM_QPSK) {
 	      samples_per_symbol = modem.adev[0].samples_per_sec / (modem.achan[c].baud / 2);
@@ -137,14 +141,19 @@ static void send_packet (char *str)
 	      samples_per_symbol = modem.adev[0].samples_per_sec / modem.achan[c].baud;
 	    }
 
-	    // for 1200 baud, 44100/sec, this should be 0 to 360.
-	    n = samples_per_symbol * 10 * (float)my_rand() / (float)MY_RAND_MAX;
+	    // Provide enough time for the DCD to drop.
+	    // Then throw in a random amount of time so that receiving
+	    // DPLL will need to adjust to a new phase.
+
+	    n = samples_per_symbol * (32 + (float)my_rand() / (float)MY_RAND_MAX );
 
-	    //dw_printf ("Random 0-360 = %d\n", n);
 	    for (j=0; j<n; j++) {
 	      gen_tone_put_sample (c, 0, 0);
 	    }
 #endif
+	    hdlc_send_flags (c, 8, 0);
+	    hdlc_send_flags (c, 8, 0);
+	    hdlc_send_flags (c, 8, 0);
 	    hdlc_send_flags (c, 8, 0);
 	    hdlc_send_frame (c, fbuf, flen, 0, modem.fx25_xmit_enable);
 	    hdlc_send_flags (c, 2, 1);
diff --git a/src/hdlc_rec.c b/src/hdlc_rec.c
index e6abecd..00b69c5 100644
--- a/src/hdlc_rec.c
+++ b/src/hdlc_rec.c
@@ -101,10 +101,6 @@ struct hdlc_state_s {
 	int frame_len;			/* Number of octets in frame_buf. */
 					/* Should be in range of 0 .. MAX_FRAME_LEN. */
 
-	int data_detect;		/* True when HDLC data is detected. */
-					/* This will not be triggered by voice or other */
-					/* noise or even tones.  */
-
 	rrbb_t rrbb;			/* Handle for bit array for raw received bits. */
 					
 };
@@ -130,6 +126,7 @@ static int was_init = 0;
 
 static struct audio_s *g_audio_p;
 
+
 void hdlc_rec_init (struct audio_s *pa)
 {
 	int ch, sub, slice;
@@ -203,6 +200,7 @@ static int my_rand (void) {
  *		is_scrambled - Is the data scrambled?
  *
  *		descram_state - Current descrambler state.  (not used - remove)
+ *				Not so fast - plans to add new parameter.  PSK already provides it.
  *					
  *
  * Description:	This is called once for each received bit.
@@ -285,94 +283,6 @@ void hdlc_rec_bit (int chan, int subchan, int slice, int raw, int is_scrambled,
 	  H->flag4_det |= 0x80000000;
 	}
 
-
-/*
- * "Data Carrier detect" function based on data patterns rather than
- * audio signal strength.
- *
- * Idle time, at beginning of transmission should be filled
- * with the special "flag" characters.
- *
- * Idle time of all zero bits (alternating tones at maximum rate)
- * has also been observed rarely. It is easy to understand the reasoning.
- * The tones alternate at the maximum rate, making it symmetrical and providing
- * the most opportunity for the PLL to lock on to the edges.
- * It also violates the published protocol spec.
- *
- * Recognize zero(s) followed by a single flag even though it violates the spec.
- *
- * It has been reported that the TinyTrak4 does this.
- * https://groups.yahoo.com/neo/groups/direwolf_packet/conversations/messages/1207
- */
-
-/*
- * Originally, this looked for 4 flags in a row or 3 zeros and a flag. 
- * Is that too fussy?
- * Here are the numbers of start of DCD for our favorite Track 2 test.
- *
- *	7e7e7e7e  504 	7e000000  32  	
- *	7e7e7e--  513   7e0000--  33	
- *	7e7e----  555   7e00----  42	
- *	7e------ 2088
- *					
- * I don't think we want to look for a single flag because that would
- * make DCD too sensitive to noise and it would interfere with waiting for a 
- * clear channel to transmit.  Even a two byte match causes a lot of flickering
- * when listening to live signals.  Let's try 3 and see how that works out.
- */
-
-
-	//if (H->flag4_det == 0x7e7e7e7e) {
-	if ((H->flag4_det & 0xffffff00) == 0x7e7e7e00) {		// three seems good
-	//if ((H->flag4_det & 0xffff0000) == 0x7e7e0000) {		// two in a row
-	//if ((H->flag4_det & 0xff000000) == 0x7e000000) {		// single flag
-	  if ( ! H->data_detect) {
-	    H->data_detect = 1;
-	    dcd_change (chan, subchan, slice, 1);
-	  }
-	}
-	//else if (H->flag4_det == 0x7e000000) {	
-	else if ((H->flag4_det & 0xffffff00) == 0x7e000000) {	
-	//else if ((H->flag4_det & 0xffff0000) == 0x7e000000) {	
-	  
-	  if ( ! H->data_detect) {
-	    H->data_detect = 1;
-	    dcd_change (chan, subchan, slice, 1);
-	  }
-	}
-
-
-/* 
- * Loss of signal should result in lack of transitions.
- * (all '1' bits) for at least a little while.
- *
- * When this was written, I was only concerned about 1200 baud.
- * For 9600, added later, there is a (de)scrambling function.
- * So if there is no change in the signal, we would get pseudo random bits here.
- * Maybe we need to put in another check earlier so DCD is not held on too long
- * after loss of signal for 9600.
- * No, that would not be a good idea.  part of a valid frame, when scrambled,
- * could have seven or more "1" bits in a row.
- * Needs more study.
- */
-
-  
-	if (H->pat_det == 0xff) {	
-	  
-	  if ( H->data_detect ) {
-	    H->data_detect = 0;
-	    dcd_change (chan, subchan, slice, 0);
-	  }
-	}
-
-
-/*
- * End of data carrier detect.  
- * 
- * The rest is concerned with framing.
- */
-
-
 	rrbb_append_bit (H->rrbb, raw);
 
 	if (H->pat_det == 0x7e) {
@@ -554,47 +464,10 @@ void hdlc_rec_bit (int chan, int subchan, int slice, int raw, int is_scrambled,
 	}
 }
 
-
-
-/*-------------------------------------------------------------------
- *
- * Name:        hdlc_rec_gathering
- *
- * Purpose:     Report whether bits are currently being gathered into a frame.
- *		This is used to influence the PLL inertia.
- *		The idea is that the PLL should be a little more agreeable to
- *		synchronize with the incoming data stream when not in a frame
- *		and resist changing a little more when capturing a frame.
- *
- * Inputs:	chan
- *		subchan
- *		slice
- *
- * Returns:	True if we are currently gathering bits.
- *		In this case we want the PLL to have more inertia.
- *
- * Discussion:	This simply returns the data carrier detect state.
- *		A couple other variations were tried but turned out to
- *		be slightly worse.
- *
- *--------------------------------------------------------------------*/
-
-int hdlc_rec_gathering (int chan, int subchan, int slice)
-{
-	assert (chan >= 0 && chan < MAX_CHANS);
-	assert (subchan >= 0 && subchan < MAX_SUBCHANS);
-	assert (slice >= 0 && slice < MAX_SLICERS);
-
-	// Counts from 	     Track 1 & Track 2
-	// data_detect		992	988
-	// olen>=0		992	985
-	// OR-ed		992	985
-
-	return ( hdlc_state[chan][subchan][slice].data_detect );
-
-} /* end hdlc_rec_gathering */
-
-
+// TODO:  Data Carrier Detect (DCD) is now based on DPLL lock
+// rather than data patterns found here.
+// It would make sense to move the next 2 functions to demod.c
+// because this is done at the modem level, rather than HDLC decoder.
 
 /*-------------------------------------------------------------------
  *
diff --git a/test/scripts/check-modem19200 b/test/scripts/check-modem19200
index 8d08a8e..ae49e46 100755
--- a/test/scripts/check-modem19200
+++ b/test/scripts/check-modem19200
@@ -3,5 +3,5 @@
 @GEN_PACKETS_BIN@ -r 96000 -B19200 -a 170 -o test19.wav
 @ATEST_BIN@ -B19200 -F0 -L4 test19.wav
 @GEN_PACKETS_BIN@ -r 96000 -B19200 -n 100 -o test19.wav
-@ATEST_BIN@ -B19200 -F0 -L60 -G64 test19.wav
-@ATEST_BIN@ -B19200 -F1 -L64 -G68 test19.wav
+@ATEST_BIN@ -B19200 -F0 -L60 -G66 test19.wav
+@ATEST_BIN@ -B19200 -F1 -L64 -G69 test19.wav
diff --git a/test/scripts/check-modem2400-a b/test/scripts/check-modem2400-a
index 1faa7d1..33dfebf 100755
--- a/test/scripts/check-modem2400-a
+++ b/test/scripts/check-modem2400-a
@@ -1,5 +1,5 @@
 @CUSTOM_SHELL_SHABANG@
 
 @GEN_PACKETS_BIN@ -B2400 -j -n 100 -o test24-a.wav
-@ATEST_BIN@ -B2400 -j -F0 -L76 -G80 test24-a.wav
-@ATEST_BIN@ -B2400 -j -F1 -L84 -G88 test24-a.wav
+@ATEST_BIN@ -B2400 -j -F0 -L76 -G83 test24-a.wav
+@ATEST_BIN@ -B2400 -j -F1 -L84 -G89 test24-a.wav
diff --git a/test/scripts/check-modem2400-b b/test/scripts/check-modem2400-b
index e1823a6..913a608 100755
--- a/test/scripts/check-modem2400-b
+++ b/test/scripts/check-modem2400-b
@@ -1,5 +1,5 @@
 @CUSTOM_SHELL_SHABANG@
 
 @GEN_PACKETS_BIN@ -B2400 -J -n 100 -o test24-b.wav
-@ATEST_BIN@ -B2400 -J -F0 -L84 -G88 test24-b.wav
+@ATEST_BIN@ -B2400 -J -F0 -L81 -G88 test24-b.wav
 @ATEST_BIN@ -B2400 -J -F1 -L86 -G90 test24-b.wav
diff --git a/test/scripts/check-modem2400-g b/test/scripts/check-modem2400-g
index b505370..da7e233 100755
--- a/test/scripts/check-modem2400-g
+++ b/test/scripts/check-modem2400-g
@@ -1,4 +1,4 @@
 @CUSTOM_SHELL_SHABANG@
 
 @GEN_PACKETS_BIN@ -B2400 -g -n 100 -o test24-g.wav
-@ATEST_BIN@ -B2400 -g -F0 -L99 -G100 test24-g.wav
+@ATEST_BIN@ -B2400 -g -F0 -L99 -G101 test24-g.wav
diff --git a/test/scripts/check-modem4800 b/test/scripts/check-modem4800
index 2ad033d..7d511bb 100755
--- a/test/scripts/check-modem4800
+++ b/test/scripts/check-modem4800
@@ -1,5 +1,5 @@
 @CUSTOM_SHELL_SHABANG@
 
 @GEN_PACKETS_BIN@ -B4800 -n 100 -o test48.wav
-@ATEST_BIN@ -B4800 -F0 -L70 -G74 test48.wav
-@ATEST_BIN@ -B4800 -F1 -L79 -G84 test48.wav
+@ATEST_BIN@ -B4800 -F0 -L68 -G74 test48.wav
+@ATEST_BIN@ -B4800 -F1 -L72 -G84 test48.wav