diff --git a/DCCACK.cpp b/DCCACK.cpp
index 517d513..9d33529 100644
--- a/DCCACK.cpp
+++ b/DCCACK.cpp
@@ -27,8 +27,8 @@
 #include "DCCWaveform.h"
 #include "TrackManager.h"
 
-unsigned int DCCACK::minAckPulseDuration = 2000; // micros
-unsigned int DCCACK::maxAckPulseDuration = 20000; // micros
+unsigned long DCCACK::minAckPulseDuration = 2000; // micros
+unsigned long DCCACK::maxAckPulseDuration = 20000; // micros
   
 MotorDriver *  DCCACK::progDriver=NULL;
 ackOp  const *  DCCACK::ackManagerProg;
@@ -50,8 +50,8 @@ volatile uint8_t DCCACK::numAckSamples=0;
 uint8_t DCCACK::trailingEdgeCounter=0;
 
 
- unsigned int DCCACK::ackPulseDuration;  // micros
- unsigned long DCCACK::ackPulseStart; // micros
+unsigned long DCCACK::ackPulseDuration;  // micros
+unsigned long DCCACK::ackPulseStart; // micros
  volatile bool DCCACK::ackDetected;
  unsigned long DCCACK::ackCheckStart; // millis
  volatile bool DCCACK::ackPending;
@@ -127,7 +127,7 @@ bool DCCACK::checkResets(uint8_t numResets) {
 void DCCACK::setAckBaseline() {
       int baseline=progDriver->getCurrentRaw();
       ackThreshold= baseline + progDriver->mA2raw(ackLimitmA);
-      if (Diag::ACK) DIAG(F("ACK baseline=%d/%dmA Threshold=%d/%dmA Duration between %uus and %uus"),
+      if (Diag::ACK) DIAG(F("ACK baseline=%d/%dmA Threshold=%d/%dmA Duration between %lus and %lus"),
 			  baseline,progDriver->raw2mA(baseline),
 			  ackThreshold,progDriver->raw2mA(ackThreshold),
                           minAckPulseDuration, maxAckPulseDuration);
@@ -146,7 +146,7 @@ void DCCACK::setAckPending() {
 
 byte DCCACK::getAck() {
       if (ackPending) return (2);  // still waiting
-      if (Diag::ACK) DIAG(F("%S after %dmS max=%d/%dmA pulse=%uuS samples=%d gaps=%d"),ackDetected?F("ACK"):F("NO-ACK"), ackCheckDuration,
+      if (Diag::ACK) DIAG(F("%S after %dmS max=%d/%dmA pulse=%luS samples=%d gaps=%d"),ackDetected?F("ACK"):F("NO-ACK"), ackCheckDuration,
 			  ackMaxCurrent,progDriver->raw2mA(ackMaxCurrent), ackPulseDuration, numAckSamples, numAckGaps);
       if (ackDetected) return (1); // Yes we had an ack
       return(0);  // pending set off but not detected means no ACK.   
diff --git a/DCCACK.h b/DCCACK.h
index fa03387..c50dbbd 100644
--- a/DCCACK.h
+++ b/DCCACK.h
@@ -79,10 +79,10 @@ class DCCACK {
     static inline void setAckLimit(int mA) {
 	ackLimitmA = mA;
     }
-    static inline void setMinAckPulseDuration(unsigned int i) {
+    static inline void setMinAckPulseDuration(unsigned long i) {
 	minAckPulseDuration = i;
     }
-    static inline void setMaxAckPulseDuration(unsigned int i) {
+    static inline void setMaxAckPulseDuration(unsigned long i) {
 	maxAckPulseDuration = i;
     }
 
@@ -126,11 +126,11 @@ class DCCACK {
     static unsigned long ackCheckStart; // millis
     static unsigned int ackCheckDuration; // millis       
     
-    static unsigned int ackPulseDuration;  // micros
+    static unsigned long ackPulseDuration;  // micros
     static unsigned long ackPulseStart; // micros
 
-    static unsigned int minAckPulseDuration ; // micros
-    static unsigned int maxAckPulseDuration ; // micros
+    static unsigned long minAckPulseDuration ; // micros
+    static unsigned long maxAckPulseDuration ; // micros
     static MotorDriver* progDriver;
     static volatile uint8_t numAckGaps;
     static volatile uint8_t numAckSamples;
diff --git a/DCCEXParser.cpp b/DCCEXParser.cpp
index 431093f..34117eb 100644
--- a/DCCEXParser.cpp
+++ b/DCCEXParser.cpp
@@ -1073,15 +1073,24 @@ bool DCCEXParser::parseC(Print *stream, int16_t params, int16_t p[]) {
 #ifndef DISABLE_PROG
     case "ACK"_hk: // <D ACK ON/OFF> <D ACK [LIMIT|MIN|MAX|RETRY] Value>
 	if (params >= 3) {
+            long duration;
 	    if (p[1] == "LIMIT"_hk) {
 	      DCCACK::setAckLimit(p[2]);
-	      LCD(1, F("Ack Limit=%dmA"), p[2]);  // <D ACK LIMIT 42>
+	      LCD(1, F("Ack Limit=%dmA"), p[2]);       // <D ACK LIMIT 42>
 	    } else if (p[1] == "MIN"_hk) {
-	      DCCACK::setMinAckPulseDuration(p[2]);
-	      LCD(0, F("Ack Min=%uus"), p[2]);  //   <D ACK MIN 1500>
+	      if (params == 4 && p[3] == "MS"_hk)
+		duration = p[2] * 1000L;
+	      else
+		duration = p[2];
+	      DCCACK::setMinAckPulseDuration(duration);
+	      LCD(0, F("Ack Min=%lus"), duration);     // <D ACK MIN 1500>
 	    } else if (p[1] == "MAX"_hk) {
-	      DCCACK::setMaxAckPulseDuration(p[2]);
-	      LCD(0, F("Ack Max=%uus"), p[2]);  //   <D ACK MAX 9000>
+	      if (params == 4 && p[3] == "MS"_hk)      // <D ACK MAX 80 MS>
+		duration = p[2] * 1000L;
+	      else
+		duration = p[2];
+	      DCCACK::setMaxAckPulseDuration(duration);
+	      LCD(0, F("Ack Max=%lus"), duration);     // <D ACK MAX 9000>
 	    } else if (p[1] == "RETRY"_hk) {
 	      if (p[2] >255) p[2]=3;
 	      LCD(0, F("Ack Retry=%d Sum=%d"), p[2], DCCACK::setAckRetry(p[2]));  //   <D ACK RETRY 2>