diff --git a/components/freemodbus/Kconfig b/components/freemodbus/Kconfig
index fc48bc7d68..226ba32f2f 100644
--- a/components/freemodbus/Kconfig
+++ b/components/freemodbus/Kconfig
@@ -102,24 +102,39 @@ menu "Modbus configuration"
                 Modbus stack event processing time.
 
     config FMB_TIMER_PORT_ENABLED
-        bool "Modbus slave stack use timer for 3.5T symbol time measurement"
+        bool "Modbus stack use timer for 3.5T symbol time measurement"
         default y
         help
                 If this option is set the Modbus stack uses timer for T3.5 time measurement.
                 Else the internal UART TOUT timeout is used for 3.5T symbol time measurement.
 
     config FMB_TIMER_GROUP
-        int "Modbus Timer group number"
+        int "Slave Timer group number"
         range 0 1
         default 0
         help
-                Modbus Timer group number that is used for timeout measurement.
+                Modbus slave Timer group number that is used for timeout measurement.
 
     config FMB_TIMER_INDEX
-        int "Modbus Timer index in the group"
+        int "Slave Timer index in the group"
         range 0 1
         default 0
         help
-                Modbus Timer Index in the group that is used for timeout measurement.
+                Modbus slave Timer Index in the group that is used for timeout measurement.
+
+    config FMB_MASTER_TIMER_GROUP
+        int "Master Timer group number"
+        range 0 1
+        default FMB_TIMER_GROUP
+        help
+                Modbus master Timer group number that is used for timeout measurement.
+
+    config FMB_MASTER_TIMER_INDEX
+        int "Master Timer index"
+        range 0 1
+        default FMB_TIMER_INDEX
+        help
+                Modbus master Timer Index in the group that is used for timeout measurement.
+                Note: Modbus master and slave should have different timer index to be able to work simultaneously.
 
 endmenu
diff --git a/components/freemodbus/modbus/mb.c b/components/freemodbus/modbus/mb.c
index f0d348f7ff..c26eebfa67 100644
--- a/components/freemodbus/modbus/mb.c
+++ b/components/freemodbus/modbus/mb.c
@@ -54,7 +54,7 @@
 #endif
 
 #ifndef MB_PORT_HAS_CLOSE
-#define MB_PORT_HAS_CLOSE 0
+#define MB_PORT_HAS_CLOSE 1
 #endif
 
 /* ----------------------- Static variables ---------------------------------*/
diff --git a/components/freemodbus/port/port.h b/components/freemodbus/port/port.h
index f0070f1d2c..f53863f9a3 100644
--- a/components/freemodbus/port/port.h
+++ b/components/freemodbus/port/port.h
@@ -28,6 +28,8 @@
 
 #define MB_PORT_TAG "MB_PORT_COMMON"
 
+#define MB_PORT_HAS_CLOSE           (1) // Define to explicitly close port on destroy
+
 #define MB_PORT_CHECK(a, ret_val, str, ...) \
     if (!(a)) { \
         ESP_LOGE(MB_PORT_TAG, "%s(%u): " str, __FUNCTION__, __LINE__, ##__VA_ARGS__); \
@@ -60,13 +62,13 @@ typedef long    LONG;
 void vMBPortEnterCritical( );
 void vMBPortExitCritical( );
 
-#define ENTER_CRITICAL_SECTION( ) { ESP_LOGD(MB_PORT_TAG,"%s: Port enter critical.", __func__); \
-                                    vMBPortEnterCritical(); }
+#define ENTER_CRITICAL_SECTION( )   { ESP_LOGD(MB_PORT_TAG,"%s: Port enter critical.", __func__); \
+                                        vMBPortEnterCritical(); }
 
-#define EXIT_CRITICAL_SECTION( )  { vMBPortExitCritical(); \
-                                    ESP_LOGD(MB_PORT_TAG,"%s: Port exit critical", __func__); }
-#define MB_PORT_PARITY_GET(parity) ((parity != UART_PARITY_DISABLE) ? \
-                                        ((parity == UART_PARITY_ODD) ? MB_PAR_ODD : MB_PAR_EVEN) : MB_PAR_NONE)
+#define EXIT_CRITICAL_SECTION( )    { vMBPortExitCritical(); \
+                                        ESP_LOGD(MB_PORT_TAG,"%s: Port exit critical", __func__); }
+#define MB_PORT_PARITY_GET(parity)  ((parity != UART_PARITY_DISABLE) ? \
+                                            ((parity == UART_PARITY_ODD) ? MB_PAR_ODD : MB_PAR_EVEN) : MB_PAR_NONE)
 
 #define MB_PORT_CHECK_EVENT( event, mask ) ( event & mask )
 #define MB_PORT_CLEAR_EVENT( event, mask ) do { event &= ~mask; } while(0)
diff --git a/components/freemodbus/port/portother_m.c b/components/freemodbus/port/portother_m.c
index ffb0238087..bdc471cf70 100644
--- a/components/freemodbus/port/portother_m.c
+++ b/components/freemodbus/port/portother_m.c
@@ -55,25 +55,9 @@
 /* ----------------------- Modbus includes ----------------------------------*/
 
 /* ----------------------- Variables ----------------------------------------*/
-static UCHAR ucPortMode = 0;
 
 /* ----------------------- Start implementation -----------------------------*/
 
-UCHAR
-ucMBPortGetMode( void )
-{
-    return ucPortMode;
-}
-
-void
-vMBPortSetMode( UCHAR ucMode )
-{
-    ENTER_CRITICAL_SECTION();
-    ucPortMode = ucMode;
-    EXIT_CRITICAL_SECTION();
-}
-
-
 void
 vMBMasterPortClose( void )
 {
@@ -84,4 +68,3 @@ vMBMasterPortClose( void )
     vMBMasterPortTimerClose(  );
     vMBMasterPortEventClose(  );
 }
-
diff --git a/components/freemodbus/port/porttimer.c b/components/freemodbus/port/porttimer.c
index 2859aa0166..2340dcfcba 100644
--- a/components/freemodbus/port/porttimer.c
+++ b/components/freemodbus/port/porttimer.c
@@ -51,7 +51,7 @@
 #include "sdkconfig.h"
 #include "port_serial_slave.h"
 
-#ifdef CONFIG_FMB_TIMER_PORT_ENABLED
+#if CONFIG_FMB_TIMER_PORT_ENABLED
 
 #define MB_US50_FREQ            (20000) // 20kHz 1/20000 = 50mks
 #define MB_DISCR_TIME_US        (50)    // 50uS = one discreet for timer
@@ -61,8 +61,9 @@
 #define MB_TIMER_DIVIDER        ((TIMER_BASE_CLK / 1000000UL) * MB_DISCR_TIME_US - 1) // divider for 50uS
 #define MB_TIMER_WITH_RELOAD    (1)
 
-static const USHORT usTimerIndex = CONFIG_FMB_TIMER_INDEX; // Modbus Timer index used by stack
+static const USHORT usTimerIndex = CONFIG_FMB_TIMER_INDEX;      // Modbus Timer index used by stack
 static const USHORT usTimerGroupIndex = CONFIG_FMB_TIMER_GROUP; // Modbus Timer group index used by stack
+static timer_isr_handle_t xTimerIntHandle;                      // Timer interrupt handle
 
 static timg_dev_t *MB_TG[2] = {&TIMERG0, &TIMERG1};
 
@@ -82,7 +83,7 @@ static void IRAM_ATTR vTimerGroupIsr(void *param)
 
 BOOL xMBPortTimersInit(USHORT usTim1Timerout50us)
 {
-#ifdef CONFIG_FMB_TIMER_PORT_ENABLED
+#if CONFIG_FMB_TIMER_PORT_ENABLED
     MB_PORT_CHECK((usTim1Timerout50us > 0), FALSE,
             "Modbus timeout discreet is incorrect.");
     esp_err_t xErr;
@@ -113,7 +114,7 @@ BOOL xMBPortTimersInit(USHORT usTim1Timerout50us)
                     "failure to set alarm failure, timer_set_alarm_value() returned (0x%x).",
                     (uint32_t)xErr);
     // Register ISR for timer
-    xErr = timer_isr_register(usTimerGroupIndex, usTimerIndex, vTimerGroupIsr, NULL, ESP_INTR_FLAG_IRAM, NULL);
+    xErr = timer_isr_register(usTimerGroupIndex, usTimerIndex, vTimerGroupIsr, NULL, ESP_INTR_FLAG_LOWMED, &xTimerIntHandle);
     MB_PORT_CHECK((xErr == ESP_OK), FALSE,
                     "timer set value failure, timer_isr_register() returned (0x%x).",
                     (uint32_t)xErr);
@@ -123,7 +124,7 @@ BOOL xMBPortTimersInit(USHORT usTim1Timerout50us)
 
 void vMBPortTimersEnable()
 {
-#ifdef CONFIG_FMB_TIMER_PORT_ENABLED
+#if CONFIG_FMB_TIMER_PORT_ENABLED
     ESP_ERROR_CHECK(timer_pause(usTimerGroupIndex, usTimerIndex));
     ESP_ERROR_CHECK(timer_set_counter_value(usTimerGroupIndex, usTimerIndex, 0ULL));
     ESP_ERROR_CHECK(timer_enable_intr(usTimerGroupIndex, usTimerIndex));
@@ -133,7 +134,7 @@ void vMBPortTimersEnable()
 
 void vMBPortTimersDisable()
 {
-#ifdef CONFIG_FMB_TIMER_PORT_ENABLED
+#if CONFIG_FMB_TIMER_PORT_ENABLED
     ESP_ERROR_CHECK(timer_pause(usTimerGroupIndex, usTimerIndex));
     ESP_ERROR_CHECK(timer_set_counter_value(usTimerGroupIndex, usTimerIndex, 0ULL));
     // Disable timer interrupt
@@ -143,9 +144,10 @@ void vMBPortTimersDisable()
 
 void vMBPortTimerClose()
 {
-#ifdef CONFIG_FMB_TIMER_PORT_ENABLED
+#if CONFIG_FMB_TIMER_PORT_ENABLED
     ESP_ERROR_CHECK(timer_pause(usTimerGroupIndex, usTimerIndex));
     ESP_ERROR_CHECK(timer_disable_intr(usTimerGroupIndex, usTimerIndex));
+    ESP_ERROR_CHECK(esp_intr_free(xTimerIntHandle));
 #endif
 }
 
diff --git a/components/freemodbus/port/porttimer_m.c b/components/freemodbus/port/porttimer_m.c
index c2b5b423c5..eb48cc1a42 100644
--- a/components/freemodbus/port/porttimer_m.c
+++ b/components/freemodbus/port/porttimer_m.c
@@ -49,17 +49,15 @@
 #define MB_TIMER_DIVIDER        ((TIMER_BASE_CLK / 1000000UL) * MB_TICK_TIME_US - 1) // divider for 50uS
 #define MB_TIMER_WITH_RELOAD    (1)
 
-// Timer group and timer number to measure time (configurable in KConfig)
-#define MB_TIMER_INDEX CONFIG_FMB_TIMER_INDEX
-#define MB_TIMER_GROUP CONFIG_FMB_TIMER_GROUP
-
 #define MB_TIMER_IO_LED 0
 
 /* ----------------------- Variables ----------------------------------------*/
 static USHORT usT35TimeOut50us;
 
-static const USHORT usTimerIndex = MB_TIMER_INDEX;      // Initialize Modbus Timer index used by stack,
-static const USHORT usTimerGroupIndex = MB_TIMER_GROUP; // Timer group index used by stack
+// Initialize Modbus Timer group and index used by stack
+static const USHORT usTimerIndex = CONFIG_FMB_MASTER_TIMER_INDEX;
+static const USHORT usTimerGroupIndex = CONFIG_FMB_MASTER_TIMER_GROUP;
+static timer_isr_handle_t xTimerIntHandle;  // Timer interrupt handle
 
 static timg_dev_t *MB_TG[2] = { &TIMERG0, &TIMERG1 };
 
@@ -115,7 +113,7 @@ BOOL xMBMasterPortTimersInit(USHORT usTimeOut50us)
                     (uint32_t)xErr);
     // Register ISR for timer
     xErr = timer_isr_register(usTimerGroupIndex, usTimerIndex,
-                                vTimerGroupIsr, NULL, ESP_INTR_FLAG_IRAM, NULL);
+                                vTimerGroupIsr, NULL, ESP_INTR_FLAG_LOWMED, &xTimerIntHandle);
     MB_PORT_CHECK((xErr == ESP_OK), FALSE,
                     "timer set value failure, timer_isr_register() returned (0x%x).",
                     (uint32_t)xErr);
@@ -151,7 +149,7 @@ static BOOL xMBMasterPortTimersEnable(USHORT usTimerTics50us)
     MB_PORT_CHECK((xErr == ESP_OK), FALSE,
                             "timer start failure, timer_start() returned (0x%x).",
                             (uint32_t)xErr);
-    //ESP_LOGD(MB_PORT_TAG,"%s Init timer.", __func__);
+
     return TRUE;
 }
 
@@ -198,4 +196,5 @@ void vMBMasterPortTimerClose()
 {
     ESP_ERROR_CHECK(timer_pause(usTimerGroupIndex, usTimerIndex));
     ESP_ERROR_CHECK(timer_disable_intr(usTimerGroupIndex, usTimerIndex));
+    ESP_ERROR_CHECK(esp_intr_free(xTimerIntHandle));
 }
diff --git a/components/freemodbus/serial_master/modbus_controller/mbc_serial_master.c b/components/freemodbus/serial_master/modbus_controller/mbc_serial_master.c
index 1cd9bdcd20..088dc06792 100644
--- a/components/freemodbus/serial_master/modbus_controller/mbc_serial_master.c
+++ b/components/freemodbus/serial_master/modbus_controller/mbc_serial_master.c
@@ -141,6 +141,7 @@ static esp_err_t mbc_serial_master_destroy(void)
     MB_MASTER_CHECK((mb_error == MB_ENOERR), ESP_ERR_INVALID_STATE,
             "mb stack close failure returned (0x%x).", (uint32_t)mb_error);
     free(mbm_interface_ptr); // free the memory allocated for options
+    mbm_interface_ptr = NULL;
     return ESP_OK;
 }
 
diff --git a/components/freemodbus/serial_slave/modbus_controller/mbc_serial_slave.c b/components/freemodbus/serial_slave/modbus_controller/mbc_serial_slave.c
index c1687bc72e..61682d63f9 100644
--- a/components/freemodbus/serial_slave/modbus_controller/mbc_serial_slave.c
+++ b/components/freemodbus/serial_slave/modbus_controller/mbc_serial_slave.c
@@ -28,7 +28,7 @@
 #include "port_serial_slave.h"
 
 // Shared pointer to interface structure
-static mb_slave_interface_t* mbs_interface_ptr = NULL; // &default_interface_inst;
+static mb_slave_interface_t* mbs_interface_ptr = NULL;
 
 // Modbus task function
 static void modbus_slave_task(void *pvParameters)
@@ -36,7 +36,7 @@ static void modbus_slave_task(void *pvParameters)
     // Modbus interface must be initialized before start 
     MB_SLAVE_ASSERT(mbs_interface_ptr != NULL);
     mb_slave_options_t* mbs_opts = &mbs_interface_ptr->opts;
-    
+
     MB_SLAVE_ASSERT(mbs_opts != NULL);
     // Main Modbus stack processing cycle
     for (;;) {
@@ -129,7 +129,7 @@ static esp_err_t mbc_serial_slave_destroy(void)
     MB_SLAVE_CHECK((mb_error == MB_ENOERR), ESP_ERR_INVALID_STATE,
             "mb stack close failure returned (0x%x).", (uint32_t)mb_error);
     free(mbs_interface_ptr);
-
+    mbs_interface_ptr = NULL;
     return ESP_OK;
 }