diff --git a/FM.cpp b/FM.cpp
index 5f2e217..c455858 100644
--- a/FM.cpp
+++ b/FM.cpp
@@ -82,10 +82,8 @@ void CFM::reset()
 {
 }
 
-void CFM::setCallsign(const char* callsign, uint8_t speed, uint16_t frequency, uint8_t time, uint8_t holdoff, uint8_t highLevel, uint8_t lowLevel, bool callsignAtStart, bool callsignAtEnd)
+uint8_t CFM::setCallsign(const char* callsign, uint8_t speed, uint16_t frequency, uint8_t time, uint8_t holdoff, uint8_t highLevel, uint8_t lowLevel, bool callsignAtStart, bool callsignAtEnd)
 {
-  m_callsign.setParams(callsign, speed, frequency, lowLevel);
-
   m_callsignAtStart = callsignAtStart;
   m_callsignAtEnd   = callsignAtEnd;
 
@@ -96,25 +94,29 @@ void CFM::setCallsign(const char* callsign, uint8_t speed, uint16_t frequency, u
 
   m_holdoffTimer.setTimeout(holdoffTime, 0U);
   m_callsignTimer.setTimeout(callsignTime, 0U);
+
+  return m_callsign.setParams(callsign, speed, frequency, lowLevel);
 }
 
-void CFM::setAck(const char* rfAck, uint8_t speed, uint16_t frequency, uint8_t minTime, uint16_t delay, uint8_t level)
+uint8_t CFM::setAck(const char* rfAck, uint8_t speed, uint16_t frequency, uint8_t minTime, uint16_t delay, uint8_t level)
 {
-  m_rfAck.setParams(rfAck, speed, frequency, level);
-
   m_ackDelayTimer.setTimeout(0U, delay);
   m_ackMinTimer.setTimeout(minTime, 0U);
+
+  return m_rfAck.setParams(rfAck, speed, frequency, level);
 }
 
-void CFM::setMisc(uint16_t timeout, uint8_t timeoutLevel, uint8_t ctcssFrequency, uint8_t ctcssThreshold, uint8_t ctcssLevel, uint8_t kerchunkTime, uint8_t hangTime)
+uint8_t CFM::setMisc(uint16_t timeout, uint8_t timeoutLevel, uint8_t ctcssFrequency, uint8_t ctcssThreshold, uint8_t ctcssLevel, uint8_t kerchunkTime, uint8_t hangTime)
 {
-  m_timeoutTone.setParams(timeoutLevel);
-  m_goertzel.setParams(ctcssFrequency, ctcssThreshold);
-  m_ctcss.setParams(ctcssFrequency, ctcssLevel);
-
   m_timeoutTimer.setTimeout(timeout, 0U);
   m_kerchunkTimer.setTimeout(kerchunkTime, 0U);
   m_hangTimer.setTimeout(hangTime, 0U);
+
+  m_timeoutTone.setParams(timeoutLevel);
+
+  m_goertzel.setParams(ctcssFrequency, ctcssThreshold);
+
+  return m_ctcss.setParams(ctcssFrequency, ctcssLevel);
 }
 
 void CFM::stateMachine(bool validSignal, uint8_t length)
diff --git a/FM.h b/FM.h
index eab9450..ef5aac5 100644
--- a/FM.h
+++ b/FM.h
@@ -47,9 +47,9 @@ 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 callsignAtStart, bool callsignAtEnd);
-  void setAck(const char* rfAck, 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);
+  uint8_t setCallsign(const char* callsign, uint8_t speed, uint16_t frequency, uint8_t time, uint8_t holdoff, uint8_t highLevel, uint8_t lowLevel, bool callsignAtStart, bool callsignAtEnd);
+  uint8_t setAck(const char* rfAck, uint8_t speed, uint16_t frequency, uint8_t minTime, uint16_t delay, uint8_t level);
+  uint8_t setMisc(uint16_t timeout, uint8_t timeoutLevel, uint8_t ctcssFrequency, uint8_t ctcssThreshold, uint8_t ctcssLevel, uint8_t kerchunkTime, uint8_t hangTime);
 
 private:
   CFMKeyer    m_callsign;
diff --git a/FMCTCSSTX.cpp b/FMCTCSSTX.cpp
index 0d8982a..737d1a3 100644
--- a/FMCTCSSTX.cpp
+++ b/FMCTCSSTX.cpp
@@ -81,7 +81,7 @@ m_n(0U)
 {
 }
 
-void CFMCTCSSTX::setParams(uint8_t frequency, uint8_t level)
+uint8_t CFMCTCSSTX::setParams(uint8_t frequency, uint8_t level)
 {
   for (uint8_t i = 0U; i < CTCSS_TABLE_LEN; i++) {
     if (CTCSS_TONES[i].m_frequency == frequency) {
@@ -91,6 +91,8 @@ void CFMCTCSSTX::setParams(uint8_t frequency, uint8_t level)
   }
 
   m_level = q15_t(level * 128);
+
+  return m_entry == NULL ? 4U : 0U;
 }
 
 void CFMCTCSSTX::getAudio(q15_t* samples, uint8_t length)
diff --git a/FMCTCSSTX.h b/FMCTCSSTX.h
index 1f2f27a..5eee1c4 100644
--- a/FMCTCSSTX.h
+++ b/FMCTCSSTX.h
@@ -31,7 +31,7 @@ class CFMCTCSSTX {
 public:
   CFMCTCSSTX();
 
-  void setParams(uint8_t frequency, uint8_t level);
+  uint8_t setParams(uint8_t frequency, uint8_t level);
 
   void getAudio(q15_t* samples, uint8_t length);
 
diff --git a/FMKeyer.cpp b/FMKeyer.cpp
index 3c9ec1f..56aa3d3 100644
--- a/FMKeyer.cpp
+++ b/FMKeyer.cpp
@@ -84,7 +84,7 @@ m_poLen(0U)
 {
 }
 
-void CFMKeyer::setParams(const char* text, uint8_t speed, uint16_t frequency, uint8_t level)
+uint8_t CFMKeyer::setParams(const char* text, uint8_t speed, uint16_t frequency, uint8_t level)
 {
   m_level = q15_t(level * 128);
 
@@ -98,7 +98,7 @@ void CFMKeyer::setParams(const char* text, uint8_t speed, uint16_t frequency, ui
 
           if (m_poLen >= 995U) {
             m_poLen = 0U;
-            return;
+            return 4U;
           }
         }
 
@@ -106,6 +106,8 @@ void CFMKeyer::setParams(const char* text, uint8_t speed, uint16_t frequency, ui
       }
     }
   }
+
+  return 0U;
 }
 
 void CFMKeyer::getAudio(q15_t* samples, uint8_t length)
diff --git a/FMKeyer.h b/FMKeyer.h
index e34e17f..dbcb011 100644
--- a/FMKeyer.h
+++ b/FMKeyer.h
@@ -25,7 +25,7 @@ class CFMKeyer {
 public:
   CFMKeyer();
 
-  void setParams(const char* text, uint8_t speed, uint16_t frequency, uint8_t level);
+  uint8_t setParams(const char* text, uint8_t speed, uint16_t frequency, uint8_t level);
 
   void getAudio(q15_t* samples, uint8_t length);
 
diff --git a/SerialPort.cpp b/SerialPort.cpp
index 0d81a09..7256571 100644
--- a/SerialPort.cpp
+++ b/SerialPort.cpp
@@ -384,9 +384,7 @@ uint8_t CSerialPort::setFMParams1(const uint8_t* data, uint8_t length)
     callsign[n] = data[i];
   callsign[n] = '\0';
 
-  fm.setCallsign(callsign, speed, frequency, time, holdoff, highLevel, lowLevel, callAtStart, callAtEnd);
-
-  return 0U;
+  return fm.setCallsign(callsign, speed, frequency, time, holdoff, highLevel, lowLevel, callAtStart, callAtEnd);
 }
 
 uint8_t CSerialPort::setFMParams2(const uint8_t* data, uint8_t length)
@@ -406,9 +404,7 @@ uint8_t CSerialPort::setFMParams2(const uint8_t* data, uint8_t length)
     ack[n] = data[i];
   ack[n] = '\0';
 
-  fm.setAck(ack, speed, frequency, minTime, delay, level);
-
-  return 0U;
+  return fm.setAck(ack, speed, frequency, minTime, delay, level);
 }
 
 uint8_t CSerialPort::setFMParams3(const uint8_t* data, uint8_t length)
@@ -426,9 +422,7 @@ uint8_t CSerialPort::setFMParams3(const uint8_t* data, uint8_t length)
   uint8_t  kerchunkTime   = data[5U];
   uint8_t  hangTime       = data[6U];
 
-  fm.setMisc(timeout, timeoutLevel, ctcssFrequency, ctcssThreshold, ctcssLevel, kerchunkTime, hangTime);
-
-  return 0U;
+  return fm.setMisc(timeout, timeoutLevel, ctcssFrequency, ctcssThreshold, ctcssLevel, kerchunkTime, hangTime);
 }
 
 uint8_t CSerialPort::setMode(const uint8_t* data, uint8_t length)