diff --git a/FM.cpp b/FM.cpp
index 466a281..f500ccb 100644
--- a/FM.cpp
+++ b/FM.cpp
@@ -40,7 +40,7 @@ void CFM::setCallsign(const char* callsign, uint8_t speed, uint16_t frequency, u
 {
 }
 
-void CFM::setAck(const char* ack, uint8_t speed, uint16_t frequency, uint16_t delay, uint8_t level)
+void CFM::setAck(const char* ack, uint8_t speed, uint16_t frequency, uint8_t minTime, uint16_t delay, uint8_t level)
 {
 }
 
diff --git a/FM.h b/FM.h
index a315869..cbbd72b 100644
--- a/FM.h
+++ b/FM.h
@@ -32,7 +32,7 @@ public:
   void reset();
 
   void setCallsign(const char* callsign, uint8_t speed, uint16_t frequency, uint8_t time, uint8_t holdoff, uint8_t highLevel, uint8_t lowLevel, bool callAtStart, bool callAtEnd);
-  void setAck(const char* ack, uint8_t speed, uint16_t frequency, uint16_t delay, uint8_t level);
+  void setAck(const char* ack, uint8_t speed, uint16_t frequency, uint8_t minTime, uint16_t delay, uint8_t level);
   void setMisc(uint16_t timeout, uint8_t timeoutLevel, uint8_t ctcssFrequency, uint8_t ctcssThreshold, uint8_t ctcssLevel, uint8_t kerchunkTime, uint8_t hangTime);
 
 private:
diff --git a/SerialPort.cpp b/SerialPort.cpp
index 872657a..62ded18 100644
--- a/SerialPort.cpp
+++ b/SerialPort.cpp
@@ -391,21 +391,22 @@ uint8_t CSerialPort::setFMParams1(const uint8_t* data, uint8_t length)
 
 uint8_t CSerialPort::setFMParams2(const uint8_t* data, uint8_t length)
 {
-  if (length < 4U)
+  if (length < 5U)
     return 4U;
 
   uint8_t  speed     = data[0U];
   uint16_t frequency = data[1U] * 10U;
-  uint16_t delay     = data[2U] * 10U;
-  uint8_t  level     = data[3U];
+  uint8_t  minTime   = data[2U];
+  uint16_t delay     = data[3U] * 10U;
+  uint8_t  level     = data[4U];
 
   char ack[50U];
   uint8_t n = 0U;
-  for (uint8_t i = 4U; i < length; i++, n++)
+  for (uint8_t i = 5U; i < length; i++, n++)
     ack[n] = data[i];
   ack[n] = '\0';
 
-  fm.setAck(ack, speed, frequency, delay, level);
+  fm.setAck(ack, speed, frequency, minTime, delay, level);
 
   return 0U;
 }