diff --git a/bacnet-stack/demo/handler/s_rp.c b/bacnet-stack/demo/handler/s_rp.c
index 9c58d9e3..932e4670 100644
--- a/bacnet-stack/demo/handler/s_rp.c
+++ b/bacnet-stack/demo/handler/s_rp.c
@@ -25,6 +25,7 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <errno.h>
+#include <string.h>
 #include "config.h"
 #include "config.h"
 #include "txbuf.h"
diff --git a/bacnet-stack/demo/handler/s_whois.c b/bacnet-stack/demo/handler/s_whois.c
index afc4caeb..52ddd525 100644
--- a/bacnet-stack/demo/handler/s_whois.c
+++ b/bacnet-stack/demo/handler/s_whois.c
@@ -25,6 +25,7 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <errno.h>
+#include <string.h>
 #include "config.h"
 #include "config.h"
 #include "txbuf.h"
diff --git a/bacnet-stack/demo/readprop/Makefile b/bacnet-stack/demo/readprop/Makefile
index be25c704..189c65af 100644
--- a/bacnet-stack/demo/readprop/Makefile
+++ b/bacnet-stack/demo/readprop/Makefile
@@ -6,10 +6,10 @@ BASEDIR = .
 #CFLAGS  = -Wall -I. -O2 -g
 # Note: you can strip out symbols using the strip command
 # to get an idea of how big the compile really is.
-#DEFINES = -DBACFILE=1 -DBACDL_ETHERNET=1
-#DEFINES = -DBACFILE=1 -DBACDL_ARCNET=1
-#DEFINES = -DBACFILE=1 -DBACDL_MSTP=1 
-DEFINES = -DBACFILE=1 -DTSM_ENABLED=1 -DBACDL_BIP=1 -DBIG_ENDIAN=0 -DPRINT_ENABLED=1
+#DEFINES = -DBACFILE=1 -DTSM_ENABLED=1 -DBIG_ENDIAN=0 -DPRINT_ENABLED=1 -DBACDL_ETHERNET=1
+#DEFINES = -DBACFILE=1 -DTSM_ENABLED=1 -DBIG_ENDIAN=0 -DPRINT_ENABLED=1 -DBACDL_ARCNET=1
+#DEFINES = -DBACFILE=1 -DTSM_ENABLED=1 -DBIG_ENDIAN=0 -DPRINT_ENABLED=1 -DBACDL_MSTP=1 
+DEFINES = -DBACFILE=1 -DTSM_ENABLED=1 -DBIG_ENDIAN=0 -DPRINT_ENABLED=1 -DBACDL_BIP=1
 BACNET_PORT = ../../ports/linux
 BACNET_OBJECT = ../object
 BACNET_HANDLER = ../handler
@@ -22,6 +22,8 @@ TARGET = bacrp
 
 SRCS = readprop.c \
        $(BACNET_PORT)/bip-init.c \
+       $(BACNET_PORT)/ethernet.c \
+       $(BACNET_PORT)/arcnet.c \
        $(BACNET_ROOT)/bip.c \
        $(BACNET_HANDLER)/txbuf.c \
        $(BACNET_HANDLER)/noserv.c \
diff --git a/bacnet-stack/demo/readprop/readprop.c b/bacnet-stack/demo/readprop/readprop.c
index cb064d8f..9daeac22 100644
--- a/bacnet-stack/demo/readprop/readprop.c
+++ b/bacnet-stack/demo/readprop/readprop.c
@@ -174,11 +174,21 @@ int main(int argc, char *argv[])
     Device_Set_Object_Instance_Number(BACNET_MAX_INSTANCE);
     address_init();
     Init_Service_Handlers();
-    /* configure standard BACnet/IP port */
-    bip_set_interface("eth0");  /* for linux */
-    bip_set_port(0xBAC0);
+#if defined(BACDL_ETHERNET)
+    /* init the physical layer */
+    if (!ethernet_init("eth0"))
+        return 1;
+#elif defined(BACDL_BIP)
+    bip_set_interface("eth0");
     if (!bip_init())
         return 1;
+    printf("bip: using port %hu\r\n", bip_get_port());
+#elif defined(BACDL_ARCNET)
+    if (!arcnet_init("arc0"))
+        return 1;
+#else
+    #error Datalink (BACDL_ETHERNET,BACDL_BIP, or BACDL_ARCNET) undefined
+#endif
     /* configure the timeout values */
     last_seconds = time(NULL);
     timeout_seconds = (Device_APDU_Timeout() / 1000) *
@@ -192,7 +202,7 @@ int main(int argc, char *argv[])
         current_seconds = time(NULL);
 
         /* returns 0 bytes on timeout */
-        pdu_len = bip_receive(&src, &Rx_Buf[0], MAX_MPDU, timeout);
+        pdu_len = datalink_receive(&src, &Rx_Buf[0], MAX_MPDU, timeout);
 
         /* process */
         if (pdu_len) {
diff --git a/bacnet-stack/ports/linux/ethernet.c b/bacnet-stack/ports/linux/ethernet.c
index 52141e1b..27454268 100644
--- a/bacnet-stack/ports/linux/ethernet.c
+++ b/bacnet-stack/ports/linux/ethernet.c
@@ -188,8 +188,9 @@ int ethernet_send_pdu(BACNET_ADDRESS * dest,    /* destination address */
     BACNET_ADDRESS src = { 0 }; /* source address for npdu*/
     uint8_t mtu[MAX_MPDU] = { 0 }; /* our buffer */
     int mtu_len = 0;
-    int len = 0;
+    int npdu_len = 0;
 
+    /* load the BACnet address for NPDU data */
     for (i = 0; i < 6; i++) {
         src.mac[i] = Ethernet_MAC_Address[i];
         src.mac_len++;
@@ -223,16 +224,16 @@ int ethernet_send_pdu(BACNET_ADDRESS * dest,    /* destination address */
     mtu[14] = 0x82;      /* DSAP for BACnet */
     mtu[15] = 0x82;      /* SSAP for BACnet */
     mtu[16] = 0x03;      /* Control byte in header */
-    len = npdu_encode_pdu(&mtu[17], dest, &src, npdu_data);
-    mtu_len = 17 + len;
+    npdu_len = npdu_encode_pdu(&mtu[17], dest, &src, npdu_data);
+    mtu_len = 17 + npdu_len;
     if ((mtu_len + pdu_len) > MAX_MPDU) {
         fprintf(stderr, "ethernet: PDU is too big to send!\n");
         return -4;
     }
     memcpy(&mtu[mtu_len], pdu, pdu_len);
     mtu_len += pdu_len;
-    /* packet length */
-    encode_unsigned16(&mtu[12],mtu_len);
+    /* packet length - only the logical portion, not the address */
+    encode_unsigned16(&mtu[12], 3 + npdu_len + pdu_len);
 
     /* Send the packet */
     bytes =