diff --git a/bacnet-stack/Makefile b/bacnet-stack/Makefile
index f6b5628b..4686e153 100644
--- a/bacnet-stack/Makefile
+++ b/bacnet-stack/Makefile
@@ -15,6 +15,7 @@ MY_BACNET_DEFINES = -DPRINT_ENABLED=1
 MY_BACNET_DEFINES += -DBACAPP_ALL
 MY_BACNET_DEFINES += -DBACFILE
 MY_BACNET_DEFINES += -DINTRINSIC_REPORTING
+MY_BACNET_DEFINES += -DBACNET_TIME_MASTER
 MY_BACNET_DEFINES += -DBACNET_PROPERTY_LISTS=1
 BACNET_DEFINES ?= $(MY_BACNET_DEFINES)
 
diff --git a/bacnet-stack/demo/handler/h_ts.c b/bacnet-stack/demo/handler/h_ts.c
index 4d636786..06ad77ed 100644
--- a/bacnet-stack/demo/handler/h_ts.c
+++ b/bacnet-stack/demo/handler/h_ts.c
@@ -26,14 +26,28 @@
 #include <stdint.h>
 #include <stdio.h>
 #include "config.h"
-#include "txbuf.h"
+#include "device.h"
+#include "datetime.h"
 #include "bacdef.h"
 #include "bacdcode.h"
 #include "timesync.h"
 #include "handlers.h"
+#include "client.h"
+#include "bacaddr.h"
 
 /** @file h_ts.c  Handles TimeSync requests. */
 
+#if defined(BACNET_TIME_MASTER)
+/* sending time sync to recipients */
+#ifndef MAX_TIME_SYNC_RECIPIENTS
+#define MAX_TIME_SYNC_RECIPIENTS 16
+#endif
+BACNET_RECIPIENT_LIST Time_Sync_Recipients[MAX_TIME_SYNC_RECIPIENTS];
+/* variable used for controlling when to
+   automatically send a TimeSynchronization request */
+static BACNET_DATE_TIME Next_Sync_Time;
+#endif
+
 #if PRINT_ENABLED
 static void show_bacnet_date_time(
     BACNET_DATE * bdate,
@@ -58,8 +72,8 @@ void handler_timesync(
     BACNET_ADDRESS * src)
 {
     int len = 0;
-    BACNET_DATE bdate;
-    BACNET_TIME btime;
+    BACNET_DATE bdate = {0};
+    BACNET_TIME btime = {0};
 
     (void) src;
     (void) service_len;
@@ -67,12 +81,16 @@ void handler_timesync(
         timesync_decode_service_request(service_request, service_len, &bdate,
         &btime);
     if (len > 0) {
+        if (datetime_is_valid(&bdate, &btime)) {
+            /* fixme: only set the time if off by some amount */
 #if PRINT_ENABLED
-        fprintf(stderr, "Received TimeSyncronization Request\r\n");
-        show_bacnet_date_time(&bdate, &btime);
+            fprintf(stderr, "Received TimeSyncronization Request\r\n");
+            show_bacnet_date_time(&bdate, &btime);
 #else
-        /* FIXME: set the time? */
+            /* FIXME: set the time?
+               Maybe only set the time if off by some amount */
 #endif
+        }
     }
 
     return;
@@ -93,12 +111,188 @@ void handler_timesync_utc(
         timesync_decode_service_request(service_request, service_len, &bdate,
         &btime);
     if (len > 0) {
+        if (datetime_is_valid(&bdate, &btime)) {
 #if PRINT_ENABLED
-        fprintf(stderr, "Received TimeSyncronization Request\r\n");
-        show_bacnet_date_time(&bdate, &btime);
+            fprintf(stderr, "Received TimeSyncronization Request\r\n");
+            show_bacnet_date_time(&bdate, &btime);
 #endif
-        /* FIXME: set the time? */
+            /* FIXME: set the time?
+               only set the time if off by some amount */
+        }
     }
 
     return;
 }
+
+#if defined(BACNET_TIME_MASTER)
+/** Handle a request to list all the timesync recipients.
+ *
+ *  Invoked by a request to read the Device object's
+ *  PROP_TIME_SYNCHRONIZATION_RECIPIENTS.
+ *  Loops through the list of timesync recipients, and, for each valid one,
+ *  adds its data to the APDU.
+ *
+ *  @param apdu [out] Buffer in which the APDU contents are built.
+ *  @param max_apdu [in] Max length of the APDU buffer.
+ *
+ *  @return How many bytes were encoded in the buffer, or
+ *   BACNET_STATUS_ABORT if the response would not fit within the buffer.
+ */
+int handler_timesync_encode_recipients(
+    uint8_t * apdu,
+    int max_apdu)
+{
+    return timesync_encode_timesync_recipients(apdu, max_apdu,
+        &Time_Sync_Recipients[0]);
+}
+#endif
+
+#if defined(BACNET_TIME_MASTER)
+bool handler_timesync_recipient_write(
+    BACNET_WRITE_PROPERTY_DATA * wp_data)
+{
+    bool status = false;
+
+    /* fixme: handle writing of the recipient list */
+    wp_data->error_class = ERROR_CLASS_PROPERTY;
+    wp_data->error_code = ERROR_CODE_WRITE_ACCESS_DENIED;
+
+    return status;
+}
+#endif
+
+#if defined(BACNET_TIME_MASTER)
+static void handler_timesync_send(
+    BACNET_DATE_TIME * current_date_time)
+{
+    unsigned index = 0;
+    bool status = false;
+
+    for (index = 0; index < MAX_TIME_SYNC_RECIPIENTS; index++) {
+        if (Time_Sync_Recipients[index].tag == 1) {
+            if (status) {
+                Send_TimeSync_Remote(
+                    &Time_Sync_Recipients[index].type.address,
+                    &current_date_time->date,
+                    &current_date_time->time);
+            }
+        }
+    }
+}
+#endif
+
+#if defined(BACNET_TIME_MASTER)
+static void handler_timesync_update(
+    uint32_t device_interval,
+    BACNET_DATE_TIME * current_date_time)
+{
+    uint32_t current_minutes = 0;
+    uint32_t next_minutes = 0;
+    uint32_t delta_minutes = 0;
+    uint32_t offset_minutes = 0;
+    uint32_t interval = 0;
+    uint32_t interval_offset = 0;
+
+    datetime_copy(&Next_Sync_Time, current_date_time);
+    if (Device_Align_Intervals()) {
+        interval_offset = Device_Interval_Offset();
+        /* If periodic time synchronization is enabled and
+           the time synchronization interval is a factor of
+           (divides without remainder) an hour or day, then
+           the beginning of the period specified for time
+           synchronization shall be aligned to the hour or
+           day, respectively. */
+        if ((60 % device_interval) == 0) {
+            /* factor of an hour alignment */
+            /* Interval_Minutes = 1  2  3  4  5  6  10  12  15  20  30  60 */
+            /* determine next interval */
+            current_minutes = Next_Sync_Time.time.min;
+            interval = current_minutes/device_interval;
+            interval++;
+            next_minutes = interval * device_interval;
+            offset_minutes = interval_offset % device_interval;
+            next_minutes += offset_minutes;
+            delta_minutes = next_minutes - current_minutes;
+            datetime_add_minutes(&Next_Sync_Time, delta_minutes);
+            Next_Sync_Time.time.sec = 0;
+            Next_Sync_Time.time.hundredths = 0;
+        } else if ((1440 % device_interval) == 0) {
+            /* factor of a day alignment */
+            /* Interval_Minutes = 1  2  3  4  5  6  8  9  10  12  15  16
+               18  20  24  30  32  36  40  45  48  60  72  80  90  96  120
+               144  160  180  240  288  360  480  720  1440   */
+            current_minutes =
+                datetime_minutes_since_midnight(&Next_Sync_Time.time);
+            interval = current_minutes/device_interval;
+            interval++;
+            next_minutes = interval * device_interval;
+            offset_minutes = interval_offset % device_interval;
+            next_minutes += offset_minutes;
+            delta_minutes = next_minutes - current_minutes;
+            datetime_add_minutes(&Next_Sync_Time, delta_minutes);
+            Next_Sync_Time.time.sec = 0;
+            Next_Sync_Time.time.hundredths = 0;
+        }
+    } else {
+        datetime_add_minutes(&Next_Sync_Time, device_interval);
+        Next_Sync_Time.time.sec = 0;
+        Next_Sync_Time.time.hundredths = 0;
+    }
+}
+#endif
+
+#if defined(BACNET_TIME_MASTER)
+bool handler_timesync_recipient_address_set(
+    unsigned index,
+    BACNET_ADDRESS *address)
+{
+    bool status = false;
+
+    if (address && (index < MAX_TIME_SYNC_RECIPIENTS)) {
+        Time_Sync_Recipients[index].tag = 1;
+        bacnet_address_copy(
+            &Time_Sync_Recipients[index].type.address,
+            address);
+        status = true;
+    }
+
+    return status;
+}
+#endif
+
+#if defined(BACNET_TIME_MASTER)
+void handler_timesync_task(
+    BACNET_DATE_TIME * current_date_time)
+{
+    int compare = 0;
+    uint32_t device_interval = 0;
+
+    device_interval = Device_Time_Sync_Interval();
+    if (device_interval) {
+        compare = datetime_compare(current_date_time, &Next_Sync_Time);
+       /* if the date/times are the same, return is 0
+          if date1 is before date2, returns negative
+          if date1 is after date2, returns positive */
+        if (compare >= 0) {
+            handler_timesync_update(device_interval, current_date_time);
+            handler_timesync_send(current_date_time);
+        }
+    }
+}
+#endif
+
+#if defined(BACNET_TIME_MASTER)
+void handler_timesync_init(void)
+{
+    unsigned i = 0;
+
+    /* connect linked list */
+    for (; i < (MAX_TIME_SYNC_RECIPIENTS-1); i++) {
+        Time_Sync_Recipients[i].next = &Time_Sync_Recipients[i+1];
+        Time_Sync_Recipients[i+1].next = NULL;
+    }
+    for (i = 0; i < MAX_TIME_SYNC_RECIPIENTS; i++) {
+        Time_Sync_Recipients[i].tag = 0xFF;
+    }
+}
+#endif
diff --git a/bacnet-stack/demo/object/device-client.c b/bacnet-stack/demo/object/device-client.c
index d5918023..10877333 100644
--- a/bacnet-stack/demo/object/device-client.c
+++ b/bacnet-stack/demo/object/device-client.c
@@ -87,8 +87,13 @@ static BACNET_DATE Local_Date;  /* rely on OS, if there is one */
    BACnet UTC offset is expressed in minutes. */
 static int32_t UTC_Offset = 5 * 60;
 static bool Daylight_Savings_Status = false;    /* rely on OS */
-/* List_Of_Session_Keys */
+#if defined(BACNET_TIME_MASTER)
+static bool Align_Intervals;
+static uint32_t Interval_Minutes;
+static uint32_t Interval_Offset_Minutes;
 /* Time_Synchronization_Recipients */
+#endif
+/* List_Of_Session_Keys */
 /* Max_Master - rely on MS/TP subsystem, if there is one */
 /* Max_Info_Frames - rely on MS/TP subsystem, if there is one */
 /* Device_Address_Binding - required, but relies on binding cache */
@@ -720,6 +725,80 @@ bool Device_Daylight_Savings_Status(void)
     return Daylight_Savings_Status;
 }
 
+#if defined(BACNET_TIME_MASTER)
+/**
+ * Sets the time sync interval in minutes
+ *
+ * @param flag
+ * This property, of type BOOLEAN, specifies whether (TRUE)
+ * or not (FALSE) clock-aligned periodic time synchronization is
+ * enabled. If periodic time synchronization is enabled and the
+ * time synchronization interval is a factor of (divides without
+ * remainder) an hour or day, then the beginning of the period
+ * specified for time synchronization shall be aligned to the hour or
+ * day, respectively. If this property is present, it shall be writable.
+ */
+bool Device_Align_Intervals_Set(bool flag)
+{
+    Align_Intervals = flag;
+
+    return true;
+}
+
+bool Device_Align_Intervals(void)
+{
+    return Align_Intervals;
+}
+
+/**
+ * Sets the time sync interval in minutes
+ *
+ * @param minutes
+ * This property, of type Unsigned, specifies the periodic
+ * interval in minutes at which TimeSynchronization and
+ * UTCTimeSynchronization requests shall be sent. If this
+ * property has a value of zero, then periodic time synchronization is
+ * disabled. If this property is present, it shall be writable.
+ */
+bool Device_Time_Sync_Interval_Set(uint32_t minutes)
+{
+    Interval_Minutes = minutes;
+
+    return true;
+}
+
+uint32_t Device_Time_Sync_Interval(void)
+{
+    return Interval_Minutes;
+}
+
+/**
+ * Sets the time sync interval offset value.
+ *
+ * @param minutes
+ * This property, of type Unsigned, specifies the offset in
+ * minutes from the beginning of the period specified for time
+ * synchronization until the actual time synchronization requests
+ * are sent. The offset used shall be the value of Interval_Offset
+ * modulo the value of Time_Synchronization_Interval;
+ * e.g., if Interval_Offset has the value 31 and
+ * Time_Synchronization_Interval is 30, the offset used shall be 1.
+ * Interval_Offset shall have no effect if Align_Intervals is
+ * FALSE. If this property is present, it shall be writable.
+ */
+bool Device_Interval_Offset_Set(uint32_t minutes)
+{
+    Interval_Offset_Minutes = minutes;
+
+    return true;
+}
+
+uint32_t Device_Interval_Offset(void)
+{
+    return Interval_Offset_Minutes;
+}
+#endif
+
 /* return the length of the apdu encoded or BACNET_STATUS_ERROR for error or
    BACNET_STATUS_ABORT for abort message */
 int Device_Read_Property_Local(
diff --git a/bacnet-stack/demo/object/device.c b/bacnet-stack/demo/object/device.c
index 948ae9d6..21caadc2 100644
--- a/bacnet-stack/demo/object/device.c
+++ b/bacnet-stack/demo/object/device.c
@@ -644,6 +644,12 @@ static const int Device_Properties_Optional[] = {
     PROP_DAYLIGHT_SAVINGS_STATUS,
     PROP_LOCATION,
     PROP_ACTIVE_COV_SUBSCRIPTIONS,
+#if defined(BACNET_TIME_MASTER)
+    PROP_TIME_SYNCHRONIZATION_RECIPIENTS,
+    PROP_TIME_SYNCHRONIZATION_INTERVAL,
+    PROP_ALIGN_INTERVALS,
+    PROP_INTERVAL_OFFSET,
+#endif
     -1
 };
 
@@ -697,8 +703,13 @@ static BACNET_DATE Local_Date;  /* rely on OS, if there is one */
    BACnet UTC offset is expressed in minutes. */
 static int32_t UTC_Offset = 5 * 60;
 static bool Daylight_Savings_Status = false;    /* rely on OS */
-/* List_Of_Session_Keys */
+#if defined(BACNET_TIME_MASTER)
+static bool Align_Intervals;
+static uint32_t Interval_Minutes;
+static uint32_t Interval_Offset_Minutes;
 /* Time_Synchronization_Recipients */
+#endif
+/* List_Of_Session_Keys */
 /* Max_Master - rely on MS/TP subsystem, if there is one */
 /* Max_Info_Frames - rely on MS/TP subsystem, if there is one */
 /* Device_Address_Binding - required, but relies on binding cache */
@@ -1263,11 +1274,90 @@ int32_t Device_UTC_Offset(void)
     return UTC_Offset;
 }
 
+void Device_UTC_Offset_Set(int16_t offset)
+{
+    UTC_Offset = offset;
+}
+
 bool Device_Daylight_Savings_Status(void)
 {
     return Daylight_Savings_Status;
 }
 
+#if defined(BACNET_TIME_MASTER)
+/**
+ * Sets the time sync interval in minutes
+ *
+ * @param flag
+ * This property, of type BOOLEAN, specifies whether (TRUE)
+ * or not (FALSE) clock-aligned periodic time synchronization is
+ * enabled. If periodic time synchronization is enabled and the
+ * time synchronization interval is a factor of (divides without
+ * remainder) an hour or day, then the beginning of the period
+ * specified for time synchronization shall be aligned to the hour or
+ * day, respectively. If this property is present, it shall be writable.
+ */
+bool Device_Align_Intervals_Set(bool flag)
+{
+    Align_Intervals = flag;
+
+    return true;
+}
+
+bool Device_Align_Intervals(void)
+{
+    return Align_Intervals;
+}
+
+/**
+ * Sets the time sync interval in minutes
+ *
+ * @param minutes
+ * This property, of type Unsigned, specifies the periodic
+ * interval in minutes at which TimeSynchronization and
+ * UTCTimeSynchronization requests shall be sent. If this
+ * property has a value of zero, then periodic time synchronization is
+ * disabled. If this property is present, it shall be writable.
+ */
+bool Device_Time_Sync_Interval_Set(uint32_t minutes)
+{
+    Interval_Minutes = minutes;
+
+    return true;
+}
+
+uint32_t Device_Time_Sync_Interval(void)
+{
+    return Interval_Minutes;
+}
+
+/**
+ * Sets the time sync interval offset value.
+ *
+ * @param minutes
+ * This property, of type Unsigned, specifies the offset in
+ * minutes from the beginning of the period specified for time
+ * synchronization until the actual time synchronization requests
+ * are sent. The offset used shall be the value of Interval_Offset
+ * modulo the value of Time_Synchronization_Interval;
+ * e.g., if Interval_Offset has the value 31 and
+ * Time_Synchronization_Interval is 30, the offset used shall be 1.
+ * Interval_Offset shall have no effect if Align_Intervals is
+ * FALSE. If this property is present, it shall be writable.
+ */
+bool Device_Interval_Offset_Set(uint32_t minutes)
+{
+    Interval_Offset_Minutes = minutes;
+
+    return true;
+}
+
+uint32_t Device_Interval_Offset(void)
+{
+    return Interval_Offset_Minutes;
+}
+#endif
+
 /* return the length of the apdu encoded or BACNET_STATUS_ERROR for error or
    BACNET_STATUS_ABORT for abort message */
 int Device_Read_Property_Local(
@@ -1481,6 +1571,29 @@ int Device_Read_Property_Local(
             apdu_len =
                 encode_application_unsigned(&apdu[0], dlmstp_max_master());
             break;
+#endif
+#if defined(BACNET_TIME_MASTER)
+        case PROP_TIME_SYNCHRONIZATION_RECIPIENTS:
+            apdu_len = handler_timesync_encode_recipients(&apdu[0], MAX_APDU);
+            if (apdu_len < 0) {
+                rpdata->error_code =
+                    ERROR_CODE_ABORT_SEGMENTATION_NOT_SUPPORTED;
+                apdu_len = BACNET_STATUS_ABORT;
+            }
+            break;
+        case PROP_TIME_SYNCHRONIZATION_INTERVAL:
+            apdu_len = encode_application_unsigned(&apdu[0],
+                Device_Time_Sync_Interval());
+            break;
+        case PROP_ALIGN_INTERVALS:
+            apdu_len =
+                encode_application_boolean(&apdu[0],
+                Device_Align_Intervals());
+            break;
+        case PROP_INTERVAL_OFFSET:
+            apdu_len = encode_application_unsigned(&apdu[0],
+                Device_Interval_Offset());
+            break;
 #endif
         case PROP_ACTIVE_COV_SUBSCRIPTIONS:
             apdu_len = handler_cov_encode_subscriptions(&apdu[0], apdu_max);
@@ -1558,6 +1671,7 @@ bool Device_Write_Property_Local(
     BACNET_APPLICATION_DATA_VALUE value;
     int object_type = 0;
     uint32_t object_instance = 0;
+    uint32_t minutes = 0;
     int temp;
 
     /* decode the some of the request */
@@ -1696,9 +1810,71 @@ bool Device_Write_Property_Local(
                     characterstring_length(&value.type.Character_String));
             }
             break;
-
-        case PROP_MAX_INFO_FRAMES:
+#if defined(BACNET_TIME_MASTER)
+        case PROP_TIME_SYNCHRONIZATION_INTERVAL:
+            if (value.tag == BACNET_APPLICATION_TAG_UNSIGNED_INT) {
+                if (value.type.Unsigned_Int < 65535) {
+                    minutes = value.type.Unsigned_Int;
+                    Device_Time_Sync_Interval_Set(minutes);
+                    status = true;
+                } else {
+                    wp_data->error_class = ERROR_CLASS_PROPERTY;
+                    wp_data->error_code = ERROR_CODE_VALUE_OUT_OF_RANGE;
+                }
+            } else {
+                wp_data->error_class = ERROR_CLASS_PROPERTY;
+                wp_data->error_code = ERROR_CODE_INVALID_DATA_TYPE;
+            }
+            break;
+        case PROP_ALIGN_INTERVALS:
+            if (value.tag == BACNET_APPLICATION_TAG_BOOLEAN) {
+                Device_Align_Intervals_Set(value.type.Boolean);
+                status = true;
+            } else {
+                wp_data->error_class = ERROR_CLASS_PROPERTY;
+                wp_data->error_code = ERROR_CODE_INVALID_DATA_TYPE;
+            }
+            break;
+        case PROP_INTERVAL_OFFSET:
+            if (value.tag == BACNET_APPLICATION_TAG_UNSIGNED_INT) {
+                if (value.type.Unsigned_Int < 65535) {
+                    minutes = value.type.Unsigned_Int;
+                    Device_Interval_Offset_Set(minutes);
+                    status = true;
+                } else {
+                    wp_data->error_class = ERROR_CLASS_PROPERTY;
+                    wp_data->error_code = ERROR_CODE_VALUE_OUT_OF_RANGE;
+                }
+            } else {
+                wp_data->error_class = ERROR_CLASS_PROPERTY;
+                wp_data->error_code = ERROR_CODE_INVALID_DATA_TYPE;
+            }
+            break;
+#else
+        case PROP_TIME_SYNCHRONIZATION_INTERVAL:
+        case PROP_ALIGN_INTERVALS:
+        case PROP_INTERVAL_OFFSET:
+            wp_data->error_class = ERROR_CLASS_PROPERTY;
+            wp_data->error_code = ERROR_CODE_UNKNOWN_PROPERTY;
+            break;
+#endif
+        case PROP_UTC_OFFSET:
+            if (value.tag == BACNET_APPLICATION_TAG_SIGNED_INT) {
+                if ((value.type.Signed_Int < (12*60)) &&
+                    (value.type.Signed_Int > (-12*60))) {
+                    Device_UTC_Offset_Set(value.type.Signed_Int);
+                    status = true;
+                } else {
+                    wp_data->error_class = ERROR_CLASS_PROPERTY;
+                    wp_data->error_code = ERROR_CODE_VALUE_OUT_OF_RANGE;
+                }
+            } else {
+                wp_data->error_class = ERROR_CLASS_PROPERTY;
+                wp_data->error_code = ERROR_CODE_INVALID_DATA_TYPE;
+            }
+           break;
 #if defined(BACDL_MSTP)
+        case PROP_MAX_INFO_FRAMES:
             status =
                 WPValidateArgType(&value, BACNET_APPLICATION_TAG_UNSIGNED_INT,
                 &wp_data->error_class, &wp_data->error_code);
@@ -1713,9 +1889,7 @@ bool Device_Write_Property_Local(
                 }
             }
             break;
-#endif
         case PROP_MAX_MASTER:
-#if defined(BACDL_MSTP)
             status =
                 WPValidateArgType(&value, BACNET_APPLICATION_TAG_UNSIGNED_INT,
                 &wp_data->error_class, &wp_data->error_code);
@@ -1730,13 +1904,18 @@ bool Device_Write_Property_Local(
                 }
             }
             break;
+#else
+        case PROP_MAX_INFO_FRAMES:
+        case PROP_MAX_MASTER:
+            wp_data->error_class = ERROR_CLASS_PROPERTY;
+            wp_data->error_code = ERROR_CODE_UNKNOWN_PROPERTY;
+            break;
 #endif
         case PROP_OBJECT_TYPE:
         case PROP_VENDOR_NAME:
         case PROP_FIRMWARE_REVISION:
         case PROP_APPLICATION_SOFTWARE_VERSION:
         case PROP_LOCAL_TIME:
-        case PROP_UTC_OFFSET:
         case PROP_LOCAL_DATE:
         case PROP_DAYLIGHT_SAVINGS_STATUS:
         case PROP_PROTOCOL_VERSION:
@@ -1749,6 +1928,9 @@ bool Device_Write_Property_Local(
         case PROP_DEVICE_ADDRESS_BINDING:
         case PROP_DATABASE_REVISION:
         case PROP_ACTIVE_COV_SUBSCRIPTIONS:
+#if defined(BACNET_TIME_MASTER)
+        case PROP_TIME_SYNCHRONIZATION_RECIPIENTS:
+#endif
             wp_data->error_class = ERROR_CLASS_PROPERTY;
             wp_data->error_code = ERROR_CODE_WRITE_ACCESS_DENIED;
             break;
diff --git a/bacnet-stack/demo/object/device.h b/bacnet-stack/demo/object/device.h
index 979c3dcd..aeb269bc 100644
--- a/bacnet-stack/demo/object/device.h
+++ b/bacnet-stack/demo/object/device.h
@@ -237,6 +237,12 @@ extern "C" {
         BACNET_DATE_TIME * DateTime);
     int32_t Device_UTC_Offset(void);
     bool Device_Daylight_Savings_Status(void);
+    bool Device_Align_Intervals(void);
+    bool Device_Align_Intervals_Set(bool flag);
+    uint32_t Device_Time_Sync_Interval(void);
+    bool Device_Time_Sync_Interval_Set(uint32_t value);
+    uint32_t Device_Interval_Offset(void);
+    bool Device_Interval_Offset_Set(uint32_t value);
 
     void Device_Property_Lists(
         const int **pRequired,
diff --git a/bacnet-stack/demo/server/main.c b/bacnet-stack/demo/server/main.c
index dfa78523..ddd153eb 100644
--- a/bacnet-stack/demo/server/main.c
+++ b/bacnet-stack/demo/server/main.c
@@ -146,6 +146,9 @@ static void Init_Service_Handlers(
     apdu_set_confirmed_handler(SERVICE_CONFIRMED_GET_ALARM_SUMMARY,
         handler_get_alarm_summary);
 #endif /* defined(INTRINSIC_REPORTING) */
+#if defined(BACNET_TIME_MASTER)
+    handler_timesync_init();
+#endif
 }
 
 static void print_usage(const char *filename)
@@ -196,6 +199,9 @@ int main(
     uint32_t elapsed_milliseconds = 0;
     uint32_t address_binding_tmr = 0;
     uint32_t recipient_scan_tmr = 0;
+#if defined(BACNET_TIME_MASTER)
+    BACNET_DATE_TIME bdatetime;
+#endif
 #if defined(BAC_UCI)
     int uciId = 0;
     struct uci_context *ctx;
@@ -282,6 +288,10 @@ int main(
             trend_log_timer(elapsed_seconds);
 #if defined(INTRINSIC_REPORTING)
             Device_local_reporting();
+#endif
+#if defined(BACNET_TIME_MASTER)
+            Device_getCurrentDateTime(&bdatetime);
+            handler_timesync_task(&bdatetime);
 #endif
         }
         handler_cov_task();
diff --git a/bacnet-stack/include/handlers.h b/bacnet-stack/include/handlers.h
index ea7a8ec6..095f6638 100644
--- a/bacnet-stack/include/handlers.h
+++ b/bacnet-stack/include/handlers.h
@@ -195,8 +195,6 @@ extern "C" {
         void);
     bool handler_timesync_recipient_write(
         BACNET_WRITE_PROPERTY_DATA * wp_data);
-    bool handler_timesync_interval_set(
-        uint32_t minutes);
     bool handler_timesync_recipient_address_set(
         unsigned index,
         BACNET_ADDRESS * address);