diff --git a/bacnet-stack/bacapp.c b/bacnet-stack/bacapp.c
index bdd98aeb..14ad3021 100644
--- a/bacnet-stack/bacapp.c
+++ b/bacnet-stack/bacapp.c
@@ -523,10 +523,17 @@ int bacapp_data_len(uint8_t * apdu, int max_apdu_len,
                     max_apdu_len - apdu_len, &application_value);
             }
             apdu_len += len;
-            if (opening_tag_number_counter)
-                total_len += len;
-            /* ERROR! */
+            if (opening_tag_number_counter) {
+                if (len > 0) {
+                    total_len += len;
+                } else {
+                    /* error: len is not incrementing */
+                    total_len = -1;
+                    break;
+                }
+            }
             if (apdu_len > max_apdu_len) {
+                /* error: exceeding our buffer limit */
                 total_len = -1;
                 break;
             }
diff --git a/bacnet-stack/config.h b/bacnet-stack/config.h
index 0ef4934f..cc742d75 100644
--- a/bacnet-stack/config.h
+++ b/bacnet-stack/config.h
@@ -1,34 +1,62 @@
 #ifndef CONFIG_H
 #define CONFIG_H
 
+/* Note: these defines can be defined in your makefile or project 
+   or here or not defined and defaults will be used */
+
 /* declare a single physical layer using your compiler define.
    see datalink.h for possible defines. */
+#if !(defined(BACDL_ETHERNET) || defined(BACDL_ARCNET) || defined(BACDL_MSTP) || defined(BACDL_BIP))
+    #define BACDL_BIP
+#endif
+
+/* optional debug info for BACnet/IP datalink layers */
+#if defined(BACDL_BIP)
+    #if !defined(BIP_DEBUG)
+        #define BIP_DEBUG
+    #endif
+#endif
+
+/* Define your processor architecture as Big Endian or Little Endian */
+#if !defined(BIG_ENDIAN)
+    #define BIG_ENDIAN 0
+#endif
+
+/* Define your Vendor Identifier assigned by ASHRAE */
+#if !defined(BACNET_VENDOR_ID)
+    #define BACNET_VENDOR_ID 260
+#endif
 
 /* Max number of bytes in an APDU. */
 /* Typical sizes are 50, 128, 206, 480, 1024, and 1476 octets */
 /* This is used in constructing messages and to tell others our limits */
 /* 50 is the minimum; adjust to your memory and physical layer constraints */
 /* Lon=206, MS/TP=480, ARCNET=480, Ethernet=1476 */
-#ifndef MAX_APDU
-  /* #define MAX_APDU 50 */
-  #define MAX_APDU 480
-  /* #define MAX_APDU 1476 */
+#if !defined(MAX_APDU)
+    /* #define MAX_APDU 50 */
+    #define MAX_APDU 480
+    /* #define MAX_APDU 1476 */
 #endif
 /* for confirmed messages, this is the number of transactions */
 /* that we hold in a queue waiting for timeout. */
 /* Configure to zero if you don't want any confirmed messages */
 /* Configure from 1..255 for number of outstanding confirmed */
 /* requests available. */
-#ifndef MAX_TSM_TRANSACTIONS
-  #define MAX_TSM_TRANSACTIONS 255
+#if !defined(MAX_TSM_TRANSACTIONS)
+    #define MAX_TSM_TRANSACTIONS 255
 #endif
 /* The address cache is used for binding to BACnet devices */
 /* The number of entries corresponds to the number of */
 /* devices that might respond to an I-Am on the network. */
 /* If your device is a simple server and does not need to bind, */
 /* then you don't need to use this. */
-#ifndef MAX_ADDRESS_CACHE
-  #define MAX_ADDRESS_CACHE 255
+#if !defined(MAX_ADDRESS_CACHE)
+    #define MAX_ADDRESS_CACHE 255
+#endif
+
+/* some modules have debugging enabled using PRINT_ENABLED */
+#if !defined(PRINT_ENABLED)
+    #define PRINT_ENABLED 0
 #endif
 
 #endif
diff --git a/bacnet-stack/datalink.h b/bacnet-stack/datalink.h
index 6fe82273..de75b5af 100644
--- a/bacnet-stack/datalink.h
+++ b/bacnet-stack/datalink.h
@@ -34,6 +34,8 @@
 #ifndef DATALINK_H
 #define DATALINK_H
 
+#include "config.h"
+
 #if defined(BACDL_ETHERNET)
 #include "ethernet.h"
 
diff --git a/bacnet-stack/demo/object/device.c b/bacnet-stack/demo/object/device.c
index 925ece07..3e6a4ff0 100644
--- a/bacnet-stack/demo/object/device.c
+++ b/bacnet-stack/demo/object/device.c
@@ -44,12 +44,11 @@
 #include "wp.h"                 /* write property handling */
 #include "version.h"
 #include "device.h"             /* me */
-#if BACFILE
-#include "bacfile.h"            /* object list dependency */
-#endif
-#if defined(BACDL_MSTP)
-#include "dlmstp.h"
+#include "datalink.h"
+#if defined(BACFILE)
+    #include "bacfile.h"            /* object list dependency */
 #endif
+
 /* These three arrays are used by the ReadPropertyMultiple handler */
 static const int Device_Properties_Required[] =
 {
@@ -120,8 +119,7 @@ static uint32_t Object_Instance_Number = 0;
 static char Object_Name[16] = "SimpleServer";
 static BACNET_DEVICE_STATUS System_Status = STATUS_OPERATIONAL;
 static char Vendor_Name[16] = "ASHRAE";
-/* FIXME: your vendor id assigned by ASHRAE */
-static uint16_t Vendor_Identifier = 0;
+static uint16_t Vendor_Identifier = BACNET_VENDOR_ID;
 static char Model_Name[16] = "GNU";
 static char Application_Software_Version[16] = "1.0";
 static char Location[16] = "USA";
@@ -389,7 +387,7 @@ unsigned Device_Object_List_Count(void)
     count += Life_Safety_Point_Count();
     count += Load_Control_Count();
     count += Multistate_Output_Count();
-#if BACFILE
+#if defined(BACFILE)
     count += bacfile_count();
 #endif
 
@@ -525,7 +523,7 @@ bool Device_Object_List_Identifier(unsigned array_index,
         }
     }
     /* file objects */
-#if BACFILE
+#if defined(BACFILE)
     if (!status) {
         /* normalize the index since
            we know it is not the previous objects */
@@ -605,7 +603,7 @@ char *Device_Valid_Object_Id(int object_type, uint32_t object_instance)
     case OBJECT_MULTI_STATE_OUTPUT:
         name = Multistate_Output_Name(object_instance);
         break;
-#if BACFILE
+#if defined(BACFILE)
     case OBJECT_FILE:
         name = bacfile_name(object_instance);
         break;
@@ -754,7 +752,7 @@ int Device_Encode_Property_APDU(uint8_t * apdu,
         if (Multistate_Output_Count())
             bitstring_set_bit(&bit_string, OBJECT_MULTI_STATE_OUTPUT,
                 true);
-#if BACFILE
+#if defined(BACFILE)
         if (bacfile_count())
             bitstring_set_bit(&bit_string, OBJECT_FILE, true);
 #endif
@@ -1172,15 +1170,19 @@ uint32_t Multistate_Output_Index_To_Instance(unsigned index)
     return index;
 }
 
+#if defined(BACFILE)
 uint32_t bacfile_count(void)
 {
     return 0;
 }
+#endif
 
+#if defined(BACFILE)
 uint32_t bacfile_index_to_instance(unsigned find_index)
 {
     return find_index;
 }
+#endif
 
 int main(void)
 {
diff --git a/bacnet-stack/ports/atmega168/device.c b/bacnet-stack/ports/atmega168/device.c
index 99929bb2..c7f1681a 100644
--- a/bacnet-stack/ports/atmega168/device.c
+++ b/bacnet-stack/ports/atmega168/device.c
@@ -115,10 +115,9 @@ void Device_Set_System_Status(BACNET_DEVICE_STATUS status)
         System_Status = status;
 }
 
-/* FIXME: put your vendor ID here! */
 uint16_t Device_Vendor_Identifier(void)
 {
-    return 0;
+    return BACNET_VENDOR_ID;
 }
 
 uint8_t Device_Protocol_Version(void)
diff --git a/bacnet-stack/ports/pic18f6720/device.c b/bacnet-stack/ports/pic18f6720/device.c
index 64754396..9e7dbdd1 100644
--- a/bacnet-stack/ports/pic18f6720/device.c
+++ b/bacnet-stack/ports/pic18f6720/device.c
@@ -112,10 +112,9 @@ void Device_Set_System_Status(BACNET_DEVICE_STATUS status)
         System_Status = status;
 }
 
-/* FIXME: put your vendor ID here! */
 uint16_t Device_Vendor_Identifier(void)
 {
-    return 0;
+    return BACNET_VENDOR_ID;
 }
 
 uint8_t Device_Protocol_Version(void)
diff --git a/bacnet-stack/ports/win32/dlmstp.c b/bacnet-stack/ports/win32/dlmstp.c
index 5651ecec..451bb275 100644
--- a/bacnet-stack/ports/win32/dlmstp.c
+++ b/bacnet-stack/ports/win32/dlmstp.c
@@ -444,8 +444,8 @@ bool dlmstp_init(char *ifname)
     MSTP_Port.InputBufferSize = sizeof(RxBuffer);
     MSTP_Port.OutputBuffer = &TxBuffer[0];
     MSTP_Port.OutputBufferSize = sizeof(TxBuffer);
-    MSTP_Init.SilenceTimer = Timer_Silence;
-    MSTP_Init.SilenceTimerReset = Timer_Silence_Reset;
+    MSTP_Port.SilenceTimer = Timer_Silence;
+    MSTP_Port.SilenceTimerReset = Timer_Silence_Reset;
     MSTP_Init(&MSTP_Port);
 #if 0
     uint8_t data;