diff --git a/bacnet-stack/demo/handler/s_ts.c b/bacnet-stack/demo/handler/s_ts.c
index 8d755964..baadc80b 100644
--- a/bacnet-stack/demo/handler/s_ts.c
+++ b/bacnet-stack/demo/handler/s_ts.c
@@ -45,13 +45,13 @@
 
 /** @file s_ts.c  Send TimeSync requests. */
 
-void Send_TimeSync(
+void Send_TimeSync_Remote(
+    BACNET_ADDRESS * dest,
     BACNET_DATE * bdate,
     BACNET_TIME * btime)
 {
     int len = 0;
     int pdu_len = 0;
-    BACNET_ADDRESS dest;
     int bytes_sent = 0;
     BACNET_NPDU_DATA npdu_data;
     BACNET_ADDRESS my_address;
@@ -59,13 +59,11 @@ void Send_TimeSync(
     if (!dcc_communication_enabled())
         return;
 
-    /* we could use unicast or broadcast */
-    datalink_get_broadcast_address(&dest);
     datalink_get_my_address(&my_address);
     /* encode the NPDU portion of the packet */
     npdu_encode_npdu_data(&npdu_data, false, MESSAGE_PRIORITY_NORMAL);
     pdu_len =
-        npdu_encode_pdu(&Handler_Transmit_Buffer[0], &dest, &my_address,
+        npdu_encode_pdu(&Handler_Transmit_Buffer[0], dest, &my_address,
         &npdu_data);
 
     /* encode the APDU portion of the packet */
@@ -74,7 +72,7 @@ void Send_TimeSync(
     pdu_len += len;
     /* send it out the datalink */
     bytes_sent =
-        datalink_send_pdu(&dest, &npdu_data, &Handler_Transmit_Buffer[0],
+        datalink_send_pdu(dest, &npdu_data, &Handler_Transmit_Buffer[0],
         pdu_len);
 #if PRINT_ENABLED
     if (bytes_sent <= 0)
@@ -83,6 +81,16 @@ void Send_TimeSync(
 #endif
 }
 
+void Send_TimeSync(
+    BACNET_DATE * bdate,
+    BACNET_TIME * btime)
+{
+    BACNET_ADDRESS dest;
+
+    datalink_get_broadcast_address(&dest);
+    Send_TimeSync_Remote(&dest, bdate, btime);
+}
+
 void Send_TimeSyncUTC(
     BACNET_DATE * bdate,
     BACNET_TIME * btime)
diff --git a/bacnet-stack/include/client.h b/bacnet-stack/include/client.h
index b318bf65..baee6ff4 100644
--- a/bacnet-stack/include/client.h
+++ b/bacnet-stack/include/client.h
@@ -168,6 +168,10 @@ extern "C" {
     void Send_TimeSync(
         BACNET_DATE * bdate,
         BACNET_TIME * btime);
+    void Send_TimeSync_Remote(
+        BACNET_ADDRESS * dest,
+        BACNET_DATE * bdate,
+        BACNET_TIME * btime);
     void Send_TimeSyncUTC(
         BACNET_DATE * bdate,
         BACNET_TIME * btime);
diff --git a/bacnet-stack/include/handlers.h b/bacnet-stack/include/handlers.h
index 5ca772f5..229c8c2c 100644
--- a/bacnet-stack/include/handlers.h
+++ b/bacnet-stack/include/handlers.h
@@ -176,15 +176,27 @@ extern "C" {
         uint16_t service_len,
         BACNET_ADDRESS * src);
 
+    /* time synchronization handlers */
     void handler_timesync(
         uint8_t * service_request,
         uint16_t service_len,
         BACNET_ADDRESS * src);
-
     void handler_timesync_utc(
         uint8_t * service_request,
         uint16_t service_len,
         BACNET_ADDRESS * src);
+    /* time sync master features */
+    int handler_timesync_encode_recipients(
+        uint8_t * apdu,
+        int max_apdu);
+    void handler_timesync_task(void);
+    void handler_timesync_init(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);
 
     void handler_read_property_multiple(
         uint8_t * service_request,
diff --git a/bacnet-stack/include/timesync.h b/bacnet-stack/include/timesync.h
index feea60f6..e6684ae5 100644
--- a/bacnet-stack/include/timesync.h
+++ b/bacnet-stack/include/timesync.h
@@ -28,6 +28,23 @@
 #include <stdbool.h>
 #include "bacdef.h"
 
+struct BACnet_Recipient_List;
+typedef struct BACnet_Recipient_List {
+    /*
+        BACnetRecipient ::= CHOICE {
+            device [0] BACnetObjectIdentifier,
+            address [1] BACnetAddress
+        }
+    */
+    uint8_t tag;
+    union {
+        BACNET_OBJECT_ID device;
+        BACNET_ADDRESS address;
+    } type;
+    /* simple linked list */
+    struct BACnet_Recipient_List *next;
+} BACNET_RECIPIENT_LIST;
+
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
@@ -63,6 +80,15 @@ extern "C" {
         BACNET_DATE * my_date,
         BACNET_TIME * my_time);
 
+    int timesync_encode_timesync_recipients(
+        uint8_t * apdu,
+        unsigned max_apdu,
+        BACNET_RECIPIENT_LIST *recipient);
+    int timesync_decode_timesync_recipients(
+        uint8_t * apdu,
+        unsigned apdu_len,
+        BACNET_RECIPIENT_LIST *recipient);
+
 #ifdef TEST
 #include "ctest.h"
     void testTimeSync(
diff --git a/bacnet-stack/src/timesync.c b/bacnet-stack/src/timesync.c
index 04deacd1..c07c0b7a 100644
--- a/bacnet-stack/src/timesync.c
+++ b/bacnet-stack/src/timesync.c
@@ -113,11 +113,304 @@ int timesync_decode_service_request(
     return len;
 }
 
+/** Handle a request to encode the list of 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 one,
+ *  adds its data to the APDU.
+ *
+ *   BACnetRecipient ::= CHOICE {
+ *       device [0] BACnetObjectIdentifier,
+ *       address [1] BACnetAddress
+ *   }
+ *
+ *   BACnetAddress ::= SEQUENCE {
+ *       network-number Unsigned16, -- A value of 0 indicates the local network
+ *       mac-address OCTET STRING -- A string of length 0 indicates a broadcast
+ *   }
+ *
+ *  @param apdu [out] Buffer in which the APDU contents are built.
+ *  @param max_apdu [in] Max length of the APDU buffer.
+ *  @param recipient [in] BACNET_RECIPIENT_LIST type linked list of recipients.
+ *
+ *  @return How many bytes were encoded in the buffer, or
+ *   BACNET_STATUS_ABORT if the response would not fit within the buffer.
+ */
+int timesync_encode_timesync_recipients(
+    uint8_t * apdu,
+    unsigned max_apdu,
+    BACNET_RECIPIENT_LIST *recipient)
+{
+    int len = 0;
+    int apdu_len = 0;
+    BACNET_OCTET_STRING octet_string;
+    BACNET_RECIPIENT_LIST *pRecipient;
+
+    pRecipient = recipient;
+    while (pRecipient != NULL) {
+        if (pRecipient->tag == 0) {
+            if (max_apdu >= (1+4)) {
+                /* CHOICE - device [0] BACnetObjectIdentifier */
+                len = encode_context_object_id(&apdu[apdu_len], 0,
+                    pRecipient->type.device.type,
+                    pRecipient->type.device.instance);
+                apdu_len += len;
+            } else {
+                return BACNET_STATUS_ABORT;
+            }
+        } else if (pRecipient->tag == 1) {
+            if (pRecipient->type.address.net) {
+                len = 1 + 3 + 2 + pRecipient->type.address.net + 1;
+            } else {
+                len = 1 + 3 + 2 + pRecipient->type.address.mac_len + 1;
+            }
+            if (max_apdu >= len) {
+                /* CHOICE - address [1] BACnetAddress - opening */
+                len = encode_opening_tag(&apdu[apdu_len], 1);
+                apdu_len += len;
+                /* network-number Unsigned16, */
+                /* -- A value of 0 indicates the local network */
+                len =
+                    encode_application_unsigned(&apdu[apdu_len],
+                    pRecipient->type.address.net);
+                apdu_len += len;
+                /* mac-address OCTET STRING */
+                /* -- A string of length 0 indicates a broadcast */
+                if (pRecipient->type.address.net == BACNET_BROADCAST_NETWORK) {
+                    octetstring_init(&octet_string, NULL, 0);
+                } else if (pRecipient->type.address.net) {
+                    octetstring_init(&octet_string,
+                    &pRecipient->type.address.adr[0],
+                    pRecipient->type.address.len);
+                } else {
+                    octetstring_init(&octet_string,
+                    &pRecipient->type.address.mac[0],
+                    pRecipient->type.address.mac_len);
+                }
+                len = encode_application_octet_string(&apdu[apdu_len],
+                    &octet_string);
+                apdu_len += len;
+                /* CHOICE - address [1] BACnetAddress - closing */
+                len = encode_closing_tag(&apdu[apdu_len], 1);
+                apdu_len += len;
+            } else {
+                /* not a valid tag - don't encode this one */
+            }
+        }
+        pRecipient = pRecipient->next;
+    }
+
+    return apdu_len;
+}
+
+/** Handle a request to decode a list of timesync recipients.
+ *
+ *  Invoked by a request to write the Device object's
+ *  PROP_TIME_SYNCHRONIZATION_RECIPIENTS.
+ *  Loops through the list of timesync recipients, and, for each one,
+ *  adds its data from the APDU.
+ *
+ *   BACnetRecipient ::= CHOICE {
+ *       device [0] BACnetObjectIdentifier,
+ *       address [1] BACnetAddress
+ *   }
+ *
+ *   BACnetAddress ::= SEQUENCE {
+ *       network-number Unsigned16, -- A value of 0 indicates the local network
+ *       mac-address OCTET STRING -- A string of length 0 indicates a broadcast
+ *   }
+ *
+ *  @param apdu [in] Buffer in which the APDU contents are read
+ *  @param max_apdu [in] length of the APDU buffer.
+ *  @param recipient [out] BACNET_RECIPIENT_LIST type linked list of recipients.
+ *
+ *  @return How many bytes were decoded from the buffer, or
+ *   BACNET_STATUS_ABORT if there was a problem decoding the buffer
+ */
+int timesync_decode_timesync_recipients(
+    uint8_t * apdu,
+    unsigned max_apdu,
+    BACNET_RECIPIENT_LIST *recipient)
+{
+    int len = 0;
+    int apdu_len = 0;
+    int tag_len = 0;
+    uint8_t tag_number = 0;
+    uint32_t len_value_type = 0;
+    uint32_t unsigned_value = 0;
+    BACNET_OCTET_STRING octet_string;
+    BACNET_RECIPIENT_LIST *pRecipient;
+
+    pRecipient = recipient;
+    while (pRecipient != NULL) {
+        /* device [0] BACnetObjectIdentifier */
+        if (decode_is_context_tag(&apdu[apdu_len], 0)) {
+            pRecipient->tag = 0;
+            len = decode_context_object_id(&apdu[apdu_len], 0,
+                &pRecipient->type.device.type,
+                &pRecipient->type.device.instance);
+            if (len < 0) {
+                return BACNET_STATUS_ABORT;
+            }
+            apdu_len += len;
+        } else if (decode_is_context_tag(&apdu[apdu_len], 1)) {
+            apdu_len += 1;
+            pRecipient->tag = 1;
+            /* network-number Unsigned16 */
+            tag_len =
+                decode_tag_number_and_value(&apdu[apdu_len], &tag_number,
+                &len_value_type);
+            apdu_len += tag_len;
+            if (tag_number != BACNET_APPLICATION_TAG_UNSIGNED_INT) {
+                return BACNET_STATUS_ABORT;
+            }
+            len = decode_unsigned(&apdu[apdu_len], len_value_type, &unsigned_value);
+            pRecipient->type.address.net = unsigned_value;
+            apdu_len += len;
+            /* mac-address OCTET STRING */
+            tag_len =
+                decode_tag_number_and_value(&apdu[apdu_len], &tag_number,
+                &len_value_type);
+            apdu_len += tag_len;
+            if (tag_number != BACNET_APPLICATION_TAG_OCTET_STRING) {
+                return BACNET_STATUS_ABORT;
+            }
+            len = decode_octet_string(&apdu[0], len_value_type,
+                &octet_string);
+            apdu_len += len;
+            if (octetstring_length(&octet_string) == 0) {
+                /* -- A string of length 0 indicates a broadcast */
+            } else if (pRecipient->type.address.net) {
+                pRecipient->type.address.len =
+                    octetstring_copy_value(
+                        &pRecipient->type.address.adr[0],
+                        sizeof(pRecipient->type.address.adr),
+                        &octet_string);
+            } else {
+                pRecipient->type.address.mac_len =
+                    octetstring_copy_value(
+                        &pRecipient->type.address.mac[0],
+                        sizeof(pRecipient->type.address.mac),
+                        &octet_string);
+            }
+        } else {
+            return BACNET_STATUS_ABORT;
+        }
+        pRecipient = pRecipient->next;
+    }
+
+    return apdu_len;
+}
+
+
 #ifdef TEST
 #include <assert.h>
 #include <string.h>
 #include "ctest.h"
 
+void testTimeSyncRecipientData(
+    Test * pTest,
+    BACNET_RECIPIENT_LIST *recipient1,
+    BACNET_RECIPIENT_LIST *recipient2)
+{
+    unsigned i = 0;
+
+    if (recipient1 && recipient2) {
+        ct_test(pTest, recipient1->tag == recipient2->tag);
+        if (recipient1->tag == 0) {
+            ct_test(pTest,
+                recipient1->type.device.type ==
+                recipient2->type.device.type);
+            ct_test(pTest,
+                recipient1->type.device.instance ==
+                recipient2->type.device.instance);
+        } else if (recipient1->tag == 1) {
+            ct_test(pTest,
+                recipient1->type.address.net ==
+                recipient2->type.address.net);
+            if (recipient1->type.address.net == BACNET_BROADCAST_NETWORK) {
+                ct_test(pTest,
+                    recipient1->type.address.mac_len ==
+                    recipient2->type.address.mac_len);
+            } else if (recipient1->type.address.net) {
+                ct_test(pTest,
+                    recipient1->type.address.len ==
+                    recipient2->type.address.len);
+                for (i = 0; i < recipient1->type.address.len; i++) {
+                    ct_test(pTest,
+                        recipient1->type.address.adr[i] ==
+                        recipient2->type.address.adr[i]);
+                }
+            } else {
+                ct_test(pTest,
+                    recipient1->type.address.mac_len ==
+                    recipient2->type.address.mac_len);
+                for (i = 0; i < recipient1->type.address.mac_len; i++) {
+                    ct_test(pTest,
+                        recipient1->type.address.mac[i] ==
+                        recipient2->type.address.mac[i]);
+                }
+            }
+        } else {
+            ct_test(pTest, recipient1->tag <= 1);
+        }
+    }
+}
+
+void testTimeSyncRecipient(
+    Test * pTest)
+{
+    uint8_t apdu[480] = { 0 };
+    int len = 0;
+    BACNET_RECIPIENT_LIST recipient[4];
+    BACNET_RECIPIENT_LIST test_recipient[4];
+
+    /* link the recipient list */
+    recipient[0].next = &recipient[1];
+    recipient[1].next = &recipient[2];
+    recipient[2].next = &recipient[3];
+    recipient[3].next = NULL;
+    /* link the test recipient list */
+    test_recipient[0].next = &test_recipient[1];
+    test_recipient[1].next = &test_recipient[2];
+    test_recipient[2].next = &test_recipient[3];
+    test_recipient[3].next = NULL;
+    /* load the test data - device */
+    recipient[0].tag = 0;
+    recipient[0].type.device.type = OBJECT_DEVICE;
+    recipient[0].type.device.instance = 1234;
+    /* load the test data - address */
+    /* network = broadcast */
+    recipient[1].tag = 1;
+    recipient[1].type.address.net = BACNET_BROADCAST_NETWORK;
+    recipient[2].type.address.mac_len = 0;
+    /* network = non-zero */
+    recipient[1].tag = 1;
+    recipient[2].type.address.net = 4201;
+    recipient[2].type.address.adr[0] = 127;
+    recipient[2].type.address.len = 1;
+    /* network = zero */
+    recipient[2].type.address.net = 0;
+    recipient[2].type.address.mac[0] = 10;
+    recipient[2].type.address.mac[1] = 1;
+    recipient[2].type.address.mac[2] = 0;
+    recipient[2].type.address.mac[3] = 86;
+    recipient[2].type.address.mac[4] = 0xBA;
+    recipient[2].type.address.mac[5] = 0xC1;
+    recipient[2].type.address.mac_len = 6;
+    /* perform positive test */
+    len = timesync_encode_timesync_recipients(&apdu[0],
+        sizeof(apdu), &recipient[0]);
+    ct_test(pTest, len != BACNET_STATUS_ABORT);
+    ct_test(pTest, len > 0);
+    len = timesync_decode_timesync_recipients(&apdu[0],
+        sizeof(apdu), &test_recipient[0]);
+    ct_test(pTest, len != BACNET_STATUS_ABORT);
+    ct_test(pTest, len > 0);
+    testTimeSyncRecipientData(pTest, &recipient[0], &test_recipient[0]);
+}
+
 int timesync_decode_apdu_service(
     uint8_t * apdu,
     BACNET_UNCONFIRMED_SERVICE service,