diff --git a/bin/mbus-serial-request-data.c b/bin/mbus-serial-request-data.c
index 20e3fa6..95559eb 100755
--- a/bin/mbus-serial-request-data.c
+++ b/bin/mbus-serial-request-data.c
@@ -56,6 +56,7 @@ main(int argc, char **argv)
 
     char *device, *addr_str, *xml_result;
     int address;
+    char fcb;
     long baudrate = 9600;
 
     memset((void *)&reply, 0, sizeof(mbus_frame));
@@ -159,14 +160,16 @@ main(int argc, char **argv)
         // else MBUS_PROBE_SINGLE
         
         address = MBUS_ADDRESS_NETWORK_LAYER;
+        fcb = 0;
     }
     else
     {
         // primary addressing
         address = atoi(addr_str);
+        fcb = 1;
     }
 
-    if (mbus_send_request_frame(handle, address) == -1)
+    if (mbus_send_request_frame(handle, address, fcb) == -1)
     {
         fprintf(stderr, "Failed to send M-Bus request frame.\n");
         mbus_disconnect(handle);
diff --git a/bin/mbus-serial-select-secondary.c b/bin/mbus-serial-select-secondary.c
index 4c1066b..9fbeec0 100755
--- a/bin/mbus-serial-select-secondary.c
+++ b/bin/mbus-serial-select-secondary.c
@@ -96,7 +96,7 @@ main(int argc, char **argv)
 
     if (mbus_frame_type(&reply) == MBUS_FRAME_TYPE_ACK)
     {
-        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER) == -1)
+        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER, 0) == -1)
         {
             fprintf(stderr,"Failed to send request to selected secondary device: %s\n", mbus_error_str());
             return 1;
diff --git a/bin/mbus-tcp-request-data.c b/bin/mbus-tcp-request-data.c
index 91ff0c0..e4dc7f9 100755
--- a/bin/mbus-tcp-request-data.c
+++ b/bin/mbus-tcp-request-data.c
@@ -102,7 +102,7 @@ main(int argc, char **argv)
         }
         // else MBUS_PROBE_SINGLE
 
-        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER) == -1)
+        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER, 0) == -1)
         {
             fprintf(stderr, "Failed to send M-Bus request frame.\n");
             return 1;
@@ -113,7 +113,7 @@ main(int argc, char **argv)
         // primary addressing
 
         address = atoi(addr_str);
-        if (mbus_send_request_frame(handle, address) == -1)
+        if (mbus_send_request_frame(handle, address, 1) == -1)
         {
             fprintf(stderr, "Failed to send M-Bus request frame.\n");
             return 1;
diff --git a/bin/mbus-tcp-select-secondary.c b/bin/mbus-tcp-select-secondary.c
index 92605c6..42a6058 100755
--- a/bin/mbus-tcp-select-secondary.c
+++ b/bin/mbus-tcp-select-secondary.c
@@ -87,7 +87,7 @@ main(int argc, char **argv)
 
     if (mbus_frame_type(&reply) == MBUS_FRAME_TYPE_ACK)
     {
-        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER) == -1)
+        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER, 0) == -1)
         {
             fprintf(stderr,"Failed to send request to selected secondary device: %s\n", mbus_error_str());
             return 1;
diff --git a/mbus/mbus-protocol-aux.c b/mbus/mbus-protocol-aux.c
index 4e7f24c..3f303ca 100755
--- a/mbus/mbus-protocol-aux.c
+++ b/mbus/mbus-protocol-aux.c
@@ -1872,7 +1872,7 @@ mbus_send_application_reset_frame(mbus_handle * handle, int address, int subcode
 // send a request packet to from master to slave
 //------------------------------------------------------------------------------
 int
-mbus_send_request_frame(mbus_handle * handle, int address)
+mbus_send_request_frame(mbus_handle * handle, int address, char frame_count_bit)
 {
     int retval = 0;
     mbus_frame *frame;
@@ -1894,6 +1894,11 @@ mbus_send_request_frame(mbus_handle * handle, int address)
     frame->control = MBUS_CONTROL_MASK_REQ_UD2 | MBUS_CONTROL_MASK_DIR_M2S;
     frame->address = address;
 
+    if (frame_count_bit)
+    {
+        frame->control |= MBUS_CONTROL_MASK_FCB;
+    }
+
     if (mbus_send_frame(handle, frame) == -1)
     {
         MBUS_ERROR("%s: failed to send mbus frame.\n", __PRETTY_FUNCTION__);
@@ -2241,7 +2246,7 @@ mbus_probe_secondary_address(mbus_handle *handle, const char *mask, char *matchi
         if (ret == MBUS_PROBE_SINGLE)
         {
             /* send a data request command to find out the full address */
-            if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER) == -1)
+            if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER, 0) == -1)
             {
                 MBUS_ERROR("%s: Failed to send request to selected secondary device [mask %s]: %s.\n",
                            __PRETTY_FUNCTION__,
@@ -2320,7 +2325,7 @@ int mbus_read_slave(mbus_handle * handle, mbus_address *address, mbus_frame * re
 
     if (address->is_primary)
     {
-        if (mbus_send_request_frame(handle, address->primary) == -1)
+        if (mbus_send_request_frame(handle, address->primary, 1) == -1)
         {
             MBUS_ERROR("%s: Failed to send M-Bus request frame.\n",
                        __PRETTY_FUNCTION__);
@@ -2364,7 +2369,7 @@ int mbus_read_slave(mbus_handle * handle, mbus_address *address, mbus_frame * re
         }
         /* else MBUS_PROBE_SINGLE */
 
-        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER) == -1)
+        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER, 0) == -1)
         {
             MBUS_ERROR("%s: Failed to send M-Bus request frame.\n",
                        __PRETTY_FUNCTION__);
diff --git a/mbus/mbus-protocol-aux.h b/mbus/mbus-protocol-aux.h
index 52cfc54..67d16f3 100755
--- a/mbus/mbus-protocol-aux.h
+++ b/mbus/mbus-protocol-aux.h
@@ -288,12 +288,13 @@ int mbus_send_switch_baudrate_frame(mbus_handle * handle, int address, long baud
 /**
  * Sends request frame (REQ_UD2) to given slave using "unified" handle
  *
- * @param handle  Initialized handle
- * @param address Address (0-255)
+ * @param handle          Initialized handle
+ * @param address         Address (0-255)
+ * @param frame_count_bit Frame Count Bit (0-1)
  *
  * @return Zero when successful.
  */
-int mbus_send_request_frame(mbus_handle * handle, int address);
+int mbus_send_request_frame(mbus_handle * handle, int address, char frame_count_bit);
 
 /**
  * Sends user data frame (SND_UD) to given slave using "unified" handle