diff --git a/bin/mbus-serial-request-data-multi-reply.c b/bin/mbus-serial-request-data-multi-reply.c
index 91a2642..2213755 100755
--- a/bin/mbus-serial-request-data-multi-reply.c
+++ b/bin/mbus-serial-request-data-multi-reply.c
@@ -146,7 +146,7 @@ main(int argc, char **argv)
         }
         // else MBUS_PROBE_SINGLE
 
-        address = 253;
+        address = MBUS_ADDRESS_NETWORK_LAYER;
     } 
     else
     {
diff --git a/bin/mbus-serial-request-data.c b/bin/mbus-serial-request-data.c
index f1eaaf0..e4e22e1 100755
--- a/bin/mbus-serial-request-data.c
+++ b/bin/mbus-serial-request-data.c
@@ -113,7 +113,7 @@ main(int argc, char **argv)
         }
         // else MBUS_PROBE_SINGLE
 
-        if (mbus_send_request_frame(handle, 253) == -1)
+        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER) == -1)
         {
             fprintf(stderr, "Failed to send M-Bus request frame.\n");
             return 1;
diff --git a/bin/mbus-serial-select-secondary.c b/bin/mbus-serial-select-secondary.c
index 628d45b..ad4a883 100755
--- a/bin/mbus-serial-select-secondary.c
+++ b/bin/mbus-serial-select-secondary.c
@@ -95,7 +95,7 @@ main(int argc, char **argv)
 
     if (mbus_frame_type(&reply) == MBUS_FRAME_TYPE_ACK)
     {
-        if (mbus_send_request_frame(handle, 253) == -1)
+        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER) == -1)
 	    {
             printf("Failed to send request to selected secondary device: %s\n", mbus_error_str());
             return 1;
diff --git a/bin/mbus-tcp-raw-send.c b/bin/mbus-tcp-raw-send.c
index 8cc84f7..8f58b97 100644
--- a/bin/mbus-tcp-raw-send.c
+++ b/bin/mbus-tcp-raw-send.c
@@ -112,7 +112,7 @@ main(int argc, char **argv)
             fprintf(stderr, "%s: Error: Failed to select secondary address [%s].\n", __PRETTY_FUNCTION__, addr_str);
             return 1;    
         }
-        address = 253;
+        address = MBUS_ADDRESS_NETWORK_LAYER;
     } 
     else
     {
diff --git a/bin/mbus-tcp-request-data-multi-reply.c b/bin/mbus-tcp-request-data-multi-reply.c
index 4d932eb..e682c1e 100755
--- a/bin/mbus-tcp-request-data-multi-reply.c
+++ b/bin/mbus-tcp-request-data-multi-reply.c
@@ -106,7 +106,7 @@ main(int argc, char **argv)
         }
         // else MBUS_PROBE_SINGLE
         
-        address = 253;
+        address = MBUS_ADDRESS_NETWORK_LAYER;
     } 
     else
     {
diff --git a/bin/mbus-tcp-request-data.c b/bin/mbus-tcp-request-data.c
index 08fbca8..70aa4ee 100755
--- a/bin/mbus-tcp-request-data.c
+++ b/bin/mbus-tcp-request-data.c
@@ -95,7 +95,7 @@ main(int argc, char **argv)
         }
         // else MBUS_PROBE_SINGLE
 
-        if (mbus_send_request_frame(handle, 253) == -1)
+        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER) == -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 2970f98..e894a97 100755
--- a/bin/mbus-tcp-select-secondary.c
+++ b/bin/mbus-tcp-select-secondary.c
@@ -80,7 +80,7 @@ main(int argc, char **argv)
 
     if (mbus_frame_type(&reply) == MBUS_FRAME_TYPE_ACK)
     {
-        if (mbus_send_request_frame(handle, 253) == -1)
+        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER) == -1)
 	    {
             printf("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 0d2645e..ed6df91 100755
--- a/mbus/mbus-protocol-aux.c
+++ b/mbus/mbus-protocol-aux.c
@@ -1983,7 +1983,7 @@ mbus_probe_secondary_address(mbus_handle * handle, const char *mask, char *match
     if (ret == MBUS_PROBE_SINGLE)
     {
         /* send a data request command to find out the full address */
-        if (mbus_send_request_frame(handle, 253) == -1)
+        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER) == -1)
         {
             MBUS_ERROR("%s: Failed to send request to selected secondary device [mask %s]: %s.\n",
                        __PRETTY_FUNCTION__,
@@ -2082,7 +2082,7 @@ int mbus_read_slave(mbus_handle * handle, mbus_address *address, mbus_frame * re
         }
         /* else MBUS_PROBE_SINGLE */
 
-        if (mbus_send_request_frame(handle, 253) == -1)
+        if (mbus_send_request_frame(handle, MBUS_ADDRESS_NETWORK_LAYER) == -1)
         {
             MBUS_ERROR("%s: Failed to send M-Bus request frame.\n",
                        __PRETTY_FUNCTION__);
diff --git a/mbus/mbus-protocol.c b/mbus/mbus-protocol.c
index 1876444..9fec668 100755
--- a/mbus/mbus-protocol.c
+++ b/mbus/mbus-protocol.c
@@ -3956,8 +3956,8 @@ mbus_frame_select_secondary_pack(mbus_frame *frame, char *address)
     }
 
     frame->control  = MBUS_CONTROL_MASK_SND_UD | MBUS_CONTROL_MASK_DIR_M2S | MBUS_CONTROL_MASK_FCB;
-    frame->address  = 253;             // for addressing secondary slaves 
-    frame->control_information = 0x52; // mode 1
+    frame->address  = MBUS_ADDRESS_NETWORK_LAYER;             // for addressing secondary slaves 
+    frame->control_information = MBUS_CONTROL_INFO_SELECT_SLAVE; // mode 1
 
     frame->data_size = 8;