diff --git a/src/hm/hmPayload.h b/src/hm/hmPayload.h
index aa8fdfe6..14f8da75 100644
--- a/src/hm/hmPayload.h
+++ b/src/hm/hmPayload.h
@@ -12,6 +12,8 @@
 #include "hmRadio.h"
 #include <Arduino.h>
 
+#define HMS_TIMEOUT_SEC  30
+
 typedef struct {
     uint8_t txCmd;
     uint8_t txId;
diff --git a/src/hm/hmRadio.h b/src/hm/hmRadio.h
index 870ef457..cde5cba0 100644
--- a/src/hm/hmRadio.h
+++ b/src/hm/hmRadio.h
@@ -3,24 +3,20 @@
 // Creative Commons - http://creativecommons.org/licenses/by-nc-sa/4.0/deed
 //-----------------------------------------------------------------------------
 
-#ifndef __RADIO_H__
-#define __RADIO_H__
+#ifndef __HM_RADIO_H__
+#define __HM_RADIO_H__
 
 #include "../utils/dbg.h"
 #include <RF24.h>
 #include "../utils/crc.h"
 #include "../config/config.h"
 #include "SPI.h"
+#include "radio.h"
 
 #define SPI_SPEED           1000000
 
 #define RF_CHANNELS         5
 
-#define TX_REQ_INFO         0x15
-#define TX_REQ_DEVCONTROL   0x51
-#define ALL_FRAMES          0x80
-#define SINGLE_FRAME        0x81
-
 const char* const rf24AmpPowerNames[] = {"MIN", "LOW", "HIGH", "MAX"};
 
 
@@ -28,7 +24,7 @@ const char* const rf24AmpPowerNames[] = {"MIN", "LOW", "HIGH", "MAX"};
 // HM Radio class
 //-----------------------------------------------------------------------------
 template <uint8_t IRQ_PIN = DEF_NRF_IRQ_PIN, uint8_t CE_PIN = DEF_NRF_CE_PIN, uint8_t CS_PIN = DEF_NRF_CS_PIN, uint8_t AMP_PWR = RF24_PA_LOW, uint8_t SCLK_PIN = DEF_NRF_SCLK_PIN, uint8_t MOSI_PIN = DEF_NRF_MOSI_PIN, uint8_t MISO_PIN = DEF_NRF_MISO_PIN>
-class HmRadio {
+class HmRadio : public Radio {
     public:
         HmRadio() : mNrf24(CE_PIN, CS_PIN, SPI_SPEED) {
             if(mSerialDebug) {
@@ -349,4 +345,4 @@ class HmRadio {
         statistics_t *mStat;
 };
 
-#endif /*__RADIO_H__*/
+#endif /*__HM_RADIO_H__*/
diff --git a/src/hm/radio.h b/src/hm/radio.h
new file mode 100644
index 00000000..0eb2df5f
--- /dev/null
+++ b/src/hm/radio.h
@@ -0,0 +1,22 @@
+//-----------------------------------------------------------------------------
+// 2023 Ahoy, https://github.com/lumpapu/ahoy
+// Creative Commons - http://creativecommons.org/licenses/by-nc-sa/4.0/deed
+//-----------------------------------------------------------------------------
+
+#ifndef __RADIO_H__
+#define __RADIO_H__
+
+#define TX_REQ_INFO         0x15
+#define TX_REQ_DEVCONTROL   0x51
+#define ALL_FRAMES          0x80
+#define SINGLE_FRAME        0x81
+
+// abstract radio interface
+class Radio {
+    public:
+        virtual void sendControlPacket(uint64_t invId, uint8_t cmd, uint16_t *data, bool isRetransmit, bool isNoMI = true, bool is4chMI = false) = 0;
+        virtual void prepareDevInformCmd(uint64_t invId, uint8_t cmd, uint32_t ts, uint16_t alarmMesId, bool isRetransmit, uint8_t reqfld=TX_REQ_INFO) = 0;
+        virtual void sendCmdPacket(uint64_t invId, uint8_t mid, uint8_t pid, bool isRetransmit, bool appendCrc16=true) = 0;
+};
+
+#endif /*__RADIO_H__*/
diff --git a/src/hms/hmsPayload.h b/src/hms/hmsPayload.h
index f63f38e4..d6f1232e 100644
--- a/src/hms/hmsPayload.h
+++ b/src/hms/hmsPayload.h
@@ -11,7 +11,7 @@
 #include "../config/config.h"
 #include <Arduino.h>
 
-#define HMS_TIMEOUT_SEC  30 // 30s * 1000
+#define HMS_TIMEOUT_SEC  30
 
 typedef struct {
     uint8_t txCmd;
@@ -103,9 +103,6 @@ class HmsPayload {
         }
 
         void ivSend(Inverter<> *iv, bool highPrio = false) {
-            if ((IV_HMS != iv->ivGen) && (IV_HMT != iv->ivGen)) // only process HMS inverters
-                return;
-
             if(!highPrio) {
                 if (mPayload[iv->id].requested) {
                     if (!mPayload[iv->id].complete)
@@ -237,9 +234,6 @@ class HmsPayload {
                 if (NULL == iv)
                     continue; // skip to next inverter
 
-                if ((IV_HMS != iv->ivGen) && (IV_HMT != iv->ivGen)) // only process HMS inverters
-                    continue; // skip to next inverter
-
                 if ((mPayload[iv->id].txId != (TX_REQ_INFO + ALL_FRAMES)) && (0 != mPayload[iv->id].txId)) {
                     // no processing needed if txId is not 0x95
                     mPayload[iv->id].complete = true;
diff --git a/src/hms/hmsRadio.h b/src/hms/hmsRadio.h
index 29f23236..c8cf480c 100644
--- a/src/hms/hmsRadio.h
+++ b/src/hms/hmsRadio.h
@@ -8,14 +8,10 @@
 
 #include "../utils/dbg.h"
 #include "cmt2300a.h"
-
-#define U32_B3(val) ((uint8_t)((val >> 24) & 0xff))
-#define U32_B2(val) ((uint8_t)((val >> 16) & 0xff))
-#define U32_B1(val) ((uint8_t)((val >>  8) & 0xff))
-#define U32_B0(val) ((uint8_t)((val      ) & 0xff))
+#include "../hm/radio.h"
 
 template<class SPI, uint32_t DTU_SN = 0x81001765>
-class CmtRadio {
+class CmtRadio : public Radio {
     typedef SPI SpiType;
     typedef Cmt2300a<SpiType> CmtType;
     public:
@@ -64,7 +60,7 @@ class CmtRadio {
             return mCmtAvail;
         }
 
-        void sendControlPacket(uint64_t ivId, uint8_t cmd, uint16_t *data, bool isRetransmit) {
+        void sendControlPacket(uint64_t ivId, uint8_t cmd, uint16_t *data, bool isRetransmit, bool isNoMI = true, bool is4chMI = false) {
             DPRINT(DBG_INFO, F("sendControlPacket cmd: 0x"));
             DBGHEXLN(cmd);
             initPacket(ivId, TX_REQ_DEVCONTROL, SINGLE_FRAME);
@@ -106,7 +102,7 @@ class CmtRadio {
             sendPacket(24, isRetransmit);
         }
 
-        void sendCmdPacket(uint64_t ivId, uint8_t mid, uint8_t pid, bool isRetransmit) {
+        void sendCmdPacket(uint64_t ivId, uint8_t mid, uint8_t pid, bool isRetransmit, bool appendCrc16=true) {
             initPacket(ivId, mid, pid);
             sendPacket(10, isRetransmit);
         }