diff --git a/bacnet-stack/dlmstp.h b/bacnet-stack/dlmstp.h
index 97b2b622..e2d6c0a1 100644
--- a/bacnet-stack/dlmstp.h
+++ b/bacnet-stack/dlmstp.h
@@ -49,7 +49,7 @@ typedef struct dlmstp_packet {
     bool ready;                 /* true if ready to be sent or received */
     BACNET_ADDRESS address;     /* source address */
     uint8_t frame_type;         /* type of message */
-    unsigned pdu_len;           /* packet length */
+    uint16_t pdu_len;           /* packet length */
     uint8_t pdu[MAX_MPDU];      /* packet */
 } DLMSTP_PACKET;
 
diff --git a/bacnet-stack/mstp.c b/bacnet-stack/mstp.c
index 65d2003b..25ea0693 100644
--- a/bacnet-stack/mstp.c
+++ b/bacnet-stack/mstp.c
@@ -149,7 +149,7 @@ uint16_t MSTP_Create_Frame(uint8_t * buffer,    /* where frame is loaded */
 {                               /* number of bytes of data (up to 501) */
     uint8_t crc8 = 0xFF;        /* used to calculate the crc value */
     uint16_t crc16 = 0xFFFF;    /* used to calculate the crc value */
-    unsigned index = 0;         /* used to load the data portion of the frame */
+    uint16_t index = 0;         /* used to load the data portion of the frame */
 
     /* not enough to do a header */
     if (buffer_len < 8)
diff --git a/bacnet-stack/mstp.h b/bacnet-stack/mstp.h
index b4dd80ed..191af97a 100644
--- a/bacnet-stack/mstp.h
+++ b/bacnet-stack/mstp.h
@@ -147,7 +147,7 @@ struct mstp_port_struct_t {
     /* The number of frames sent by this node during a single token hold. */
     /* When this counter reaches the value Nmax_info_frames, the node must */
     /* pass the token. */
-    unsigned FrameCount;
+    uint8_t FrameCount;
     /* Used to accumulate the CRC on the header of a frame. */
     uint8_t HeaderCRC;
     /* Used to store the actual CRC from the header. */
@@ -223,7 +223,7 @@ struct mstp_port_struct_t {
     /* allowable address for master nodes. The value of Max_Master shall be */
     /* less than or equal to 127. If Max_Master is not writable in a node, */
     /* its value shall be 127. */
-    unsigned Nmax_master;
+    uint8_t Nmax_master;
 
     /* An array of octets, used to store octets for transmitting */
     /* OutputBuffer is indexed from 0 to OutputBufferSize-1. */
diff --git a/bacnet-stack/ports/win32/dlmstp.c b/bacnet-stack/ports/win32/dlmstp.c
index f3190443..eff4c6f8 100644
--- a/bacnet-stack/ports/win32/dlmstp.c
+++ b/bacnet-stack/ports/win32/dlmstp.c
@@ -37,6 +37,7 @@
 #define WIN32_LEAN_AND_MEAN
 #define STRICT 1
 #include <windows.h>
+#include <process.h>
 
 /* Number of MS/TP Packets Rx/Tx */
 uint16_t MSTP_Packets = 0;
@@ -127,6 +128,7 @@ uint16_t dlmstp_receive(
     uint16_t pdu_len = 0;
     DWORD wait_status = 0;
 
+    (void)max_pdu;
     /* see if there is a packet available, and a place
        to put the reply (if necessary) and process it */
     wait_status = WaitForSingleObject(Receive_Packet_Flag,timeout);
@@ -157,6 +159,7 @@ static void dlmstp_receive_fsm_task(void *pArg)
 {
     bool received_frame;
 
+    (void)pArg;
     (void)SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL);
     while (TRUE) {
         /* only do receive state machine while we don't have a frame */
@@ -180,6 +183,7 @@ static void dlmstp_master_fsm_task(void *pArg)
 {
     DWORD dwMilliseconds = 0;
 
+    (void)pArg;
     (void)SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL);
     while (TRUE) {
         switch (MSTP_Port.master_state) {
@@ -204,6 +208,7 @@ static void dlmstp_master_fsm_task(void *pArg)
 
 static void dlmstp_millisecond_task(void *pArg)
 {
+    (void)pArg;
     (void)SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL);
     for (;;) {
         dlmstp_millisecond_timer();