diff --git a/bacnet-stack/bacdcode.c b/bacnet-stack/bacdcode.c
index 024e3dd5..20aaf1a8 100644
--- a/bacnet-stack/bacdcode.c
+++ b/bacnet-stack/bacdcode.c
@@ -118,6 +118,77 @@ uint8_t encode_max_segs_max_apdu(int max_segs, int max_apdu)
     return octet;
 }
 
+// from clause 20.1.2.4 max-segments-accepted
+// and clause 20.1.2.5 max-APDU-length-accepted
+// returns the encoded octet
+int decode_max_segs(uint8_t octet)
+{
+    int max_segs = 0;
+
+    switch (octet & 0xF0)
+    {
+      case 0:
+        max_segs = 0;
+        break;
+      case 0x10:
+        max_segs = 2;
+        break;
+      case 0x20:
+        max_segs = 4;
+        break;
+      case 0x30:
+        max_segs = 8;
+        break;
+      case 0x40:
+        max_segs = 16;
+        break;
+      case 0x50:
+        max_segs = 32;
+        break;
+      case 0x60:
+        max_segs = 64;
+        break;
+      case 0x70:
+        max_segs = 65;
+        break;
+      default:
+        break;
+    }
+
+    return max_segs;
+}
+
+int decode_max_apdu(uint8_t octet)
+{
+    int max_apdu = 0;
+    
+    switch (octet & 0x0F)
+    {
+      case 0:
+        max_apdu = 50;
+        break;
+      case 1:
+        max_apdu = 128;
+        break;
+      case 2:
+        max_apdu = 206;
+        break;
+      case 3:
+        max_apdu = 480;
+        break;
+      case 4:
+        max_apdu = 1024;
+        break;
+      case 5:
+        max_apdu = 1476;
+        break;
+      default:
+        break;
+    }
+
+    return max_apdu;
+}
+
 int encode_unsigned16(uint8_t * apdu, uint16_t value)
 {
     union {
@@ -1255,6 +1326,26 @@ void testBACDCodeObject(Test * pTest)
     return;
 }
 
+void testBACDCodeMaxSegsApdu(Test * pTest)
+{
+  int max_segs[8] = {0,2,4,8,16,32,64,65};
+  int max_apdu[6] = {50,128,206,480,1024,1476};
+  int i = 0;
+  int j = 0;
+  uint8_t octet = 0;
+
+  // test 
+  for (i = 0; i < 8; i++)
+  {
+    for (j = 0; j < 6; j++)
+    {
+      octet = encode_max_segs_max_apdu(max_segs[i], max_apdu[j]);
+      ct_test(pTest, max_segs[i] == decode_max_segs(octet));
+      ct_test(pTest, max_apdu[j] == decode_max_apdu(octet));
+    }
+  }
+}
+
 #ifdef TEST_DECODE
 int main(void)
 {
@@ -1277,6 +1368,9 @@ int main(void)
     assert(rc);
     rc = ct_addTestFunction(pTest, testBACDCodeObject);
     assert(rc);
+    rc = ct_addTestFunction(pTest, testBACDCodeMaxSegsApdu);
+    assert(rc);
+    // configure output    
     ct_setStream(pTest, stdout);
     ct_run(pTest);
     (void) ct_report(pTest);
diff --git a/bacnet-stack/bacdcode.h b/bacnet-stack/bacdcode.h
index aa68817e..8c0ff926 100644
--- a/bacnet-stack/bacdcode.h
+++ b/bacnet-stack/bacdcode.h
@@ -147,5 +147,7 @@ int decode_unsigned32(uint8_t * apdu, uint32_t *value);
 // and clause 20.1.2.5 max-APDU-length-accepted
 // returns the encoded octet
 uint8_t encode_max_segs_max_apdu(int max_segs, int max_apdu);
+int decode_max_segs(uint8_t octet);
+int decode_max_apdu(uint8_t octet);
 
 #endif
diff --git a/bacnet-stack/npdu.c b/bacnet-stack/npdu.c
index 5b1ed523..8b902496 100644
--- a/bacnet-stack/npdu.c
+++ b/bacnet-stack/npdu.c
@@ -39,77 +39,7 @@
 #include "bacenum.h"
 #include "bits.h"
 #include "npdu.h"
-
-/* max-segments-accepted
-   B'000'      Unspecified number of segments accepted.
-   B'001'      2 segments accepted.
-   B'010'      4 segments accepted.
-   B'011'      8 segments accepted.
-   B'100'      16 segments accepted.
-   B'101'      32 segments accepted.
-   B'110'      64 segments accepted.
-   B'111'      Greater than 64 segments accepted.
-*/
-
-/* max-APDU-length-accepted
-   B'0000'  Up to MinimumMessageSize (50 octets)
-   B'0001'  Up to 128 octets
-   B'0010'  Up to 206 octets (fits in a LonTalk frame)
-   B'0011'  Up to 480 octets (fits in an ARCNET frame)
-   B'0100'  Up to 1024 octets
-   B'0101'  Up to 1476 octets (fits in an ISO 8802-3 frame)
-   B'0110'  reserved by ASHRAE
-   B'0111'  reserved by ASHRAE
-   B'1000'  reserved by ASHRAE
-   B'1001'  reserved by ASHRAE
-   B'1010'  reserved by ASHRAE
-   B'1011'  reserved by ASHRAE
-   B'1100'  reserved by ASHRAE
-   B'1101'  reserved by ASHRAE
-   B'1110'  reserved by ASHRAE
-   B'1111'  reserved by ASHRAE
-*/
-uint8_t npdu_encode_max_seg_max_apdu(int max_segs, int max_apdu)
-{
-    uint8_t octet = 0;
-
-    if (max_segs < 2)
-        octet = 0;
-    else if (max_segs < 4)
-        octet = 0x10;
-    else if (max_segs < 8)
-        octet = 0x20;
-    else if (max_segs < 16)
-        octet = 0x30;
-    else if (max_segs < 32)
-        octet = 0x40;
-    else if (max_segs < 64)
-        octet = 0x50;
-    else if (max_segs == 64)
-        octet = 0x60;
-    else
-        octet = 0x70;
-
-    // max_apdu must be 50 octets minimum
-    assert(max_apdu >= 50);
-    if (max_apdu == 50)
-        octet |= 0x00;
-    else if (max_apdu <= 128)
-        octet |= 0x01;
-    //fits in a LonTalk frame
-    else if (max_apdu <= 206)
-        octet |= 0x02;
-    //fits in an ARCNET or MS/TP frame
-    else if (max_apdu <= 480)
-        octet |= 0x03;
-    else if (max_apdu <= 1024)
-        octet |= 0x04;
-    // fits in an ISO 8802-3 frame
-    else if (max_apdu <= 1476)
-        octet |= 0x05;
-
-    return octet;
-}
+#include "apdu.h"
 
 int npdu_encode_raw(
   uint8_t *npdu,
@@ -339,6 +269,37 @@ int npdu_decode(
   return len;
 }
 
+void npdu_handler(
+  BACNET_ADDRESS *src,  // source address
+  uint8_t *pdu, // PDU data
+  uint16_t pdu_len) // length PDU 
+{
+  int apdu_offset = 0;
+  BACNET_ADDRESS dest = {0};
+  BACNET_NPDU_DATA npdu_data = {0};
+  
+  apdu_offset = npdu_decode(
+    &pdu[0], // data to decode
+    &dest, // destination address - get the DNET/DLEN/DADR if in there
+    src,  // source address - get the SNET/SLEN/SADR if in there
+    &npdu_data); // amount of data to decode
+  if (npdu_data.network_layer_message)
+  {
+    //FIXME: network layer message received!  Handle it!
+  }
+  else
+  {
+    apdu_handler(
+      src, 
+      npdu_data.data_expecting_reply,
+      &pdu[apdu_offset],
+      pdu_len - apdu_offset);
+  }
+
+  return;
+}
+
+
 #ifdef TEST
 #include <assert.h>
 #include <string.h>