diff --git a/ports/linux/bip-init.c b/ports/linux/bip-init.c
index 4e830d68..4c347464 100644
--- a/ports/linux/bip-init.c
+++ b/ports/linux/bip-init.c
@@ -67,7 +67,7 @@ static void debug_print_ipv4(
     const unsigned int count)
 {
     if (BIP_Debug) {
-        fprintf(
+        debug_fprintf(
             stderr, "BIP: %s %s:%hu (%u bytes)\n", str, inet_ntoa(*addr),
             ntohs(port), count);
         fflush(stderr);
@@ -301,7 +301,7 @@ int bip_send_mpdu(
     /* assumes that the driver has already been initialized */
     if (BIP_Socket < 0) {
         if (BIP_Debug) {
-            fprintf(stderr, "BIP: driver not initialized!\n");
+            debug_fprintf(stderr, "BIP: driver not initialized!\n");
             fflush(stderr);
         }
         return BIP_Socket;
@@ -423,7 +423,7 @@ uint16_t bip_receive(
             }
         } else {
             if (BIP_Debug) {
-                fprintf(stderr, "BIP: NPDU dropped!\n");
+                debug_fprintf(stderr, "BIP: NPDU dropped!\n");
                 fflush(stderr);
             }
             npdu_len = 0;
@@ -613,20 +613,20 @@ static void printRoute(struct route_info *rtInfo)
 {
     if (BIP_Debug) {
         /* Print Destination address */
-        fprintf(
+        debug_fprintf(
             stderr, "%s\t",
             rtInfo->dstAddr ? ntoa(rtInfo->dstAddr) : "0.0.0.0  ");
 
         /* Print Gateway address */
-        fprintf(
+        debug_fprintf(
             stderr, "%s\t",
             rtInfo->gateWay ? ntoa(rtInfo->gateWay) : "*.*.*.*");
 
         /* Print Interface Name */
-        fprintf(stderr, "%s\t", rtInfo->ifName);
+        debug_fprintf(stderr, "%s\t", rtInfo->ifName);
 
         /* Print Source address */
-        fprintf(
+        debug_fprintf(
             stderr, "%s\n",
             rtInfo->srcAddr ? ntoa(rtInfo->srcAddr) : "*.*.*.*");
     }
@@ -707,19 +707,19 @@ static char *ifname_default(void)
 
     /* Send the request */
     if (send(sock, nlMsg, nlMsg->nlmsg_len, 0) < 0) {
-        fprintf(stderr, "BIP: Write To Socket Failed...\n");
+        debug_fprintf(stderr, "BIP: Write To Socket Failed...\n");
         return BIP_Interface_Name;
     }
     /* Read the response */
     if ((len = readNlSock(sock, msgBuf, sizeof(msgBuf), msgSeq, getpid())) <
         0) {
-        fprintf(stderr, "BIP: Read From Socket Failed...\n");
+        debug_fprintf(stderr, "BIP: Read From Socket Failed...\n");
         return BIP_Interface_Name;
     }
     /* Parse and print the response */
     rtInfo = (struct route_info *)malloc(sizeof(struct route_info));
     if (BIP_Debug) {
-        fprintf(stderr, "Destination\tGateway\tInterface\tSource\n");
+        debug_fprintf(stderr, "Destination\tGateway\tInterface\tSource\n");
     }
     for (; NLMSG_OK(nlMsg, len); nlMsg = NLMSG_NEXT(nlMsg, len)) {
         memset(rtInfo, 0, sizeof(struct route_info));
@@ -790,8 +790,8 @@ void bip_set_interface(const char *ifname)
     }
     BIP_Address.s_addr = local_address.s_addr;
     if (BIP_Debug) {
-        fprintf(stderr, "BIP: Interface: %s\n", ifname);
-        fprintf(stderr, "BIP: Address: %s\n", inet_ntoa(local_address));
+        debug_fprintf(stderr, "BIP: Interface: %s\n", ifname);
+        debug_fprintf(stderr, "BIP: Address: %s\n", inet_ntoa(local_address));
         fflush(stderr);
     }
     /* cache interface netmask */
@@ -833,10 +833,10 @@ void bip_set_interface(const char *ifname)
     }
 #endif
     if (BIP_Debug) {
-        fprintf(
+        debug_fprintf(
             stderr, "BIP: Broadcast Address: %s\n",
             inet_ntoa(BIP_Broadcast_Addr));
-        fprintf(
+        debug_fprintf(
             stderr, "BIP: UDP Port: 0x%04X [%hu]\n", ntohs(BIP_Port),
             ntohs(BIP_Port));
         fflush(stderr);
@@ -926,7 +926,7 @@ bool bip_init(char *ifname)
         bip_set_interface(ifname_default());
     }
     if (BIP_Address.s_addr == 0) {
-        fprintf(
+        debug_fprintf(
             stderr, "BIP: Failed to get an IP address from %s!\n",
             BIP_Interface_Name);
         fflush(stderr);
diff --git a/ports/linux/bsc-event.c b/ports/linux/bsc-event.c
index ecb37618..bc42c232 100644
--- a/ports/linux/bsc-event.c
+++ b/ports/linux/bsc-event.c
@@ -17,7 +17,7 @@
 
 #undef DEBUG_PRINTF
 #if DEBUG_BSC_EVENT
-#define DEBUG_PRINTF printf
+#define DEBUG_PRINTF debug_printf
 #else
 #undef DEBUG_ENABLED
 #define DEBUG_PRINTF debug_printf_disabled
diff --git a/ports/linux/datetime-init.c b/ports/linux/datetime-init.c
index 9b5a244a..a1075a03 100644
--- a/ports/linux/datetime-init.c
+++ b/ports/linux/datetime-init.c
@@ -15,6 +15,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <time.h>
+#include "bacnet/basic/sys/debug.h"
 #include "bacport.h"
 #include "bacnet/datetime.h"
 
@@ -61,7 +62,7 @@ void datetime_timesync(BACNET_DATE *bdate, BACNET_TIME *btime, bool utc)
             Time_Offset = time_difference(tv_inp, tv_sys);
         }
 #if PRINT_ENABLED
-        printf("Time offset = %d\n", Time_Offset);
+        debug_printf("Time offset = %d\n", Time_Offset);
 #endif
     }
     return;
diff --git a/ports/linux/dlmstp.c b/ports/linux/dlmstp.c
index c4076096..1cf85ad9 100644
--- a/ports/linux/dlmstp.c
+++ b/ports/linux/dlmstp.c
@@ -982,26 +982,26 @@ bool dlmstp_init(char *ifname)
     MSTP_Port.BaudRateSet = dlmstp_set_baud_rate;
     MSTP_Init(&MSTP_Port);
 #if PRINT_ENABLED
-    fprintf(stderr, "MS/TP MAC: %02X\n", MSTP_Port.This_Station);
-    fprintf(stderr, "MS/TP Max_Master: %02X\n", MSTP_Port.Nmax_master);
-    fprintf(
+    debug_fprintf(stderr, "MS/TP MAC: %02X\n", MSTP_Port.This_Station);
+    debug_fprintf(stderr, "MS/TP Max_Master: %02X\n", MSTP_Port.Nmax_master);
+    debug_fprintf(
         stderr, "MS/TP Max_Info_Frames: %u\n",
         (unsigned)MSTP_Port.Nmax_info_frames);
-    fprintf(
+    debug_fprintf(
         stderr, "MS/TP RxBuf[%u] TxBuf[%u]\n",
         (unsigned)MSTP_Port.InputBufferSize,
         (unsigned)MSTP_Port.OutputBufferSize);
-    fprintf(
+    debug_fprintf(
         stderr,
         "MS/TP SlaveModeEnabled"
         ": %s\n",
         (MSTP_Port.SlaveNodeEnabled ? "true" : "false"));
-    fprintf(
+    debug_fprintf(
         stderr,
         "MS/TP ZeroConfigEnabled"
         ": %s\n",
         (MSTP_Port.ZeroConfigEnabled ? "true" : "false"));
-    fprintf(
+    debug_fprintf(
         stderr,
         "MS/TP CheckAutoBaud"
         ": %s\n",
diff --git a/ports/linux/rs485.c b/ports/linux/rs485.c
index d16c9e87..146cc9c9 100644
--- a/ports/linux/rs485.c
+++ b/ports/linux/rs485.c
@@ -35,6 +35,7 @@
 #include "bacnet/datalink/mstp.h"
 #include "rs485.h"
 #include "bacnet/basic/sys/fifo.h"
+#include "bacnet/basic/sys/debug.h"
 
 #include <sys/select.h>
 #include <sys/time.h>
@@ -156,7 +157,7 @@ bool RS485_Set_Baud_Rate(uint32_t baud)
         termios2_tcsetattr(RS485_Handle, TCSAFLUSH, &newtio);
 
 #if PRINT_ENABLED
-        fprintf(stdout, "RS485 Baud Rate %u\n", RS485_Baud);
+        debug_fprintf(stdout, "RS485 Baud Rate %u\n", RS485_Baud);
         fflush(stdout);
 #endif
     }
@@ -296,7 +297,7 @@ void RS485_Cleanup(void)
 void RS485_Initialize(void)
 {
 #if PRINT_ENABLED
-    fprintf(stdout, "RS485 Interface: %s\n", RS485_Port_Name);
+    debug_printf("RS485 Interface: %s\n", RS485_Port_Name);
 #endif
     /*
        Open device for reading and writing.
diff --git a/ports/linux/websocket-global.c b/ports/linux/websocket-global.c
index 1ed0c91c..6b8734ef 100644
--- a/ports/linux/websocket-global.c
+++ b/ports/linux/websocket-global.c
@@ -51,13 +51,13 @@ static volatile int websocket_dispatch_mutex_cnt = 0;
 
 void bsc_websocket_global_lock_dbg(char *f, int line)
 {
-    printf(
+    debug_printf(
         "bsc_websocket_global_lock_dbg() >>> %s:%d lock_cnt %d tid = %ld\n", f,
         line, websocket_mutex_cnt, pthread_self());
     websocket_mutex_cnt++;
     fflush(stdout);
     pthread_mutex_lock(&websocket_mutex);
-    printf(
+    debug_printf(
         "bsc_websocket_global_lock_dbg() <<< lock_cnt %d tid = %ld\n",
         websocket_mutex_cnt, pthread_self());
     fflush(stdout);
@@ -65,13 +65,13 @@ void bsc_websocket_global_lock_dbg(char *f, int line)
 
 void bsc_websocket_global_unlock_dbg(char *f, int line)
 {
-    printf(
+    debug_printf(
         "bsc_websocket_global_unlock_dbg() >>> %s:%d lock_cnt %d tid = %ld\n",
         f, line, websocket_mutex_cnt, pthread_self());
     websocket_mutex_cnt--;
     fflush(stdout);
     pthread_mutex_unlock(&websocket_mutex);
-    printf(
+    debug_printf(
         "bsc_websocket_global_unlock_dbg() <<< lock_cnt %d tid = %ld\n",
         websocket_mutex_cnt, pthread_self());
     fflush(stdout);
@@ -79,13 +79,13 @@ void bsc_websocket_global_unlock_dbg(char *f, int line)
 
 void bws_dispatch_lock_dbg(char *f, int line)
 {
-    printf(
+    debug_printf(
         "bws_dispatch_lock_dbg() >>> %s:%d lock_cnt %d tid = %ld\n", f, line,
         websocket_dispatch_mutex_cnt, pthread_self());
     websocket_dispatch_mutex_cnt++;
     fflush(stdout);
     pthread_mutex_lock(&websocket_dispatch_mutex);
-    printf(
+    debug_printf(
         "bws_dispatch_lock_dbg() <<< lock_cnt %d tid = %ld\n",
         websocket_dispatch_mutex_cnt, pthread_self());
     fflush(stdout);
@@ -93,13 +93,13 @@ void bws_dispatch_lock_dbg(char *f, int line)
 
 void bws_dispatch_unlock_dbg(char *f, int line)
 {
-    printf(
+    debug_printf(
         "bws_dispatch_unlock_dbg() >>> %s:%d lock_cnt %d  tid = %ld\n", f, line,
         websocket_dispatch_mutex_cnt, pthread_self());
     websocket_dispatch_mutex_cnt--;
     fflush(stdout);
     pthread_mutex_unlock(&websocket_dispatch_mutex);
-    printf(
+    debug_printf(
         "bws_dispatch_unlock_dbg() <<< lock_cnt %d tid = %ld\n",
         websocket_dispatch_mutex_cnt, pthread_self());
     fflush(stdout);
@@ -115,7 +115,7 @@ void bsc_websocket_init_log(void)
     if (!bsc_websocket_log_initialized) {
         bsc_websocket_log_initialized = true;
 #if DEBUG_LIBWEBSOCKETS_ENABLED == 1
-        printf("LWS_MAX_SMP = %d", LWS_MAX_SMP);
+        debug_printf("LWS_MAX_SMP = %d", LWS_MAX_SMP);
         lws_set_log_level(
             LLL_ERR | LLL_WARN | LLL_NOTICE | LLL_INFO | LLL_DEBUG |
                 LLL_PARSER | LLL_HEADER | LLL_EXT | LLL_CLIENT | LLL_LATENCY |
diff --git a/src/bacnet/basic/npdu/h_npdu.c b/src/bacnet/basic/npdu/h_npdu.c
index 26284025..8611bffc 100644
--- a/src/bacnet/basic/npdu/h_npdu.c
+++ b/src/bacnet/basic/npdu/h_npdu.c
@@ -256,13 +256,14 @@ void npdu_handler(BACNET_ADDRESS *src, uint8_t *pdu, uint16_t pdu_len)
                 }
             } else {
 #if PRINT_ENABLED
-                printf("NPDU: DNET=%u.  Discarded!\n", (unsigned)dest.net);
+                debug_printf(
+                    "NPDU: DNET=%u.  Discarded!\n", (unsigned)dest.net);
 #endif
             }
         }
     } else {
 #if PRINT_ENABLED
-        printf(
+        debug_printf(
             "NPDU: BACnet Protocol Version=%u.  Discarded!\n",
             (unsigned)pdu[0]);
 #endif
diff --git a/src/bacnet/basic/service/h_cov.c b/src/bacnet/basic/service/h_cov.c
index 78620902..8a67b520 100644
--- a/src/bacnet/basic/service/h_cov.c
+++ b/src/bacnet/basic/service/h_cov.c
@@ -459,7 +459,7 @@ static bool cov_send_request(
         return status;
     }
 #if PRINT_ENABLED
-    fprintf(stderr, "COVnotification: requested\n");
+    debug_fprintf(stderr, "COVnotification: requested\n");
 #endif
     if (!cov_subscription) {
         return status;
@@ -467,7 +467,7 @@ static bool cov_send_request(
     dest = cov_address_get(cov_subscription->dest_index);
     if (!dest) {
 #if PRINT_ENABLED
-        fprintf(stderr, "COVnotification: dest not found!\n");
+        debug_fprintf(stderr, "COVnotification: dest not found!\n");
 #endif
         return status;
     }
@@ -514,7 +514,7 @@ static bool cov_send_request(
     if (bytes_sent > 0) {
         status = true;
 #if PRINT_ENABLED
-        fprintf(stderr, "COVnotification: Sent!\n");
+        debug_fprintf(stderr, "COVnotification: Sent!\n");
 #endif
     }
 
@@ -540,18 +540,13 @@ static void cov_lifetime_expiration_handler(
         if (COV_Subscriptions[index].lifetime == 0) {
             /* expire the subscription */
 #if PRINT_ENABLED
-            fprintf(
-                stderr, "COVtimer: PID=%u ",
-                COV_Subscriptions[index].subscriberProcessIdentifier);
-            fprintf(
-                stderr, "%s %u ",
+            debug_fprintf(
+                stderr, "COVtimer: PID=%u %s %u time remaining=%u seconds\n",
+                COV_Subscriptions[index].subscriberProcessIdentifier,
                 bactext_object_type_name(
                     COV_Subscriptions[index].monitoredObjectIdentifier.type),
-                COV_Subscriptions[index].monitoredObjectIdentifier.instance);
-            fprintf(
-                stderr, "time remaining=%u seconds ",
+                COV_Subscriptions[index].monitoredObjectIdentifier.instance,
                 COV_Subscriptions[index].lifetime);
-            fprintf(stderr, "\n");
 #endif
             /* initialize with invalid COV address */
             COV_Subscriptions[index].flag.valid = false;
@@ -641,7 +636,7 @@ bool handler_cov_fsm(void)
                 if (status) {
                     COV_Subscriptions[index].flag.send_requested = true;
 #if PRINT_ENABLED
-                    fprintf(stderr, "COVtask: Marking...\n");
+                    debug_fprintf(stderr, "COVtask: Marking...\n");
 #endif
                 }
             }
@@ -707,7 +702,7 @@ bool handler_cov_fsm(void)
                     object_instance = COV_Subscriptions[index]
                                           .monitoredObjectIdentifier.instance;
 #if PRINT_ENABLED
-                    fprintf(stderr, "COVtask: Sending...\n");
+                    debug_fprintf(stderr, "COVtask: Sending...\n");
 #endif
                     /* configure the linked list for the two properties */
                     bacapp_property_value_list_init(
diff --git a/src/bacnet/datalink/dlenv.c b/src/bacnet/datalink/dlenv.c
index f9eca4ae..99199693 100644
--- a/src/bacnet/datalink/dlenv.c
+++ b/src/bacnet/datalink/dlenv.c
@@ -167,7 +167,7 @@ static int bbmd_register_as_foreign_device(void)
     }
     if (BBMD_Address_Valid) {
         if (Datalink_Debug) {
-            fprintf(
+            debug_fprintf(
                 stderr,
                 "Registering with BBMD at %u.%u.%u.%u:%u for %u seconds\n",
                 (unsigned)BBMD_Address.address[0],
@@ -199,7 +199,7 @@ static int bbmd_register_as_foreign_device(void)
                     bip_get_addr_by_name(pEnv, &BBMD_Table_Entry.dest_address);
                 if (entry_number == 1) {
                     if (Datalink_Debug) {
-                        fprintf(
+                        debug_fprintf(
                             stderr, "BBMD 1 address overridden %s=%s!\n",
                             bbmd_env, pEnv);
                     }
@@ -218,7 +218,7 @@ static int bbmd_register_as_foreign_device(void)
                     bdt_entry_port = strtol(pEnv, NULL, 0);
                     if (entry_number == 1) {
                         if (Datalink_Debug) {
-                            fprintf(
+                            debug_fprintf(
                                 stderr, "BBMD 1 port overridden %s=%s!\n",
                                 bbmd_env, pEnv);
                         }
@@ -248,7 +248,7 @@ static int bbmd_register_as_foreign_device(void)
                 bvlc_broadcast_distribution_table_entry_append(
                     bdt_table, &BBMD_Table_Entry);
                 if (Datalink_Debug) {
-                    fprintf(
+                    debug_fprintf(
                         stderr, "BBMD %4u: %u.%u.%u.%u:%u %u.%u.%u.%u\n",
                         entry_number,
                         (unsigned)BBMD_Table_Entry.dest_address.address[0],
@@ -311,7 +311,7 @@ static int bbmd6_register_as_foreign_device(void)
     pEnv = getenv("BACNET_BBMD6_ADDRESS");
     if (bvlc6_address_from_ascii(&bip6_addr, pEnv)) {
         if (Datalink_Debug) {
-            fprintf(
+            debug_fprintf(
                 stderr, "Registering with BBMD6 at %s:0x%04x for %u seconds\n",
                 pEnv, (unsigned)bip6_port, (unsigned)BBMD_TTL_Seconds);
         }
@@ -417,7 +417,7 @@ static void dlenv_network_port_bip_init(uint32_t instance)
     bip_get_addr(&addr);
     prefix = bip_get_subnet_prefix();
     if (Datalink_Debug) {
-        fprintf(
+        debug_fprintf(
             stderr, "BIP: Setting Network Port %lu address %u.%u.%u.%u:%u/%u\n",
             (unsigned long)instance, (unsigned)addr.address[0],
             (unsigned)addr.address[1], (unsigned)addr.address[2],
@@ -492,7 +492,7 @@ void dlenv_network_port_mstp_init(uint32_t instance)
         mac_address = strtol(pEnv, NULL, 0);
     }
     if (Datalink_Debug) {
-        fprintf(
+        debug_fprintf(
             stderr,
             "Network Port[%lu] mode=MSTP bitrate=%ld mac[0]=%ld "
             "max_info_frames=%ld, max_master=%ld\n",
@@ -880,7 +880,7 @@ void dlenv_maintenance_timer(uint16_t elapsed_seconds)
             if (Datalink_Debug) {
 #ifdef BACDL_MSTP
                 dlmstp_fill_statistics(&statistics);
-                fprintf(
+                debug_fprintf(
                     stderr,
                     "MSTP: Frames Rx:%u/%u/%u Tx:%u PDU Rx:%u Tx:%u "
                     "Lost:%u BadCRC:%u PFM:%u\n",
@@ -1091,7 +1091,7 @@ void dlenv_init(void)
     /* === INIT - Initialize the Datalink Here === */
     pEnv = getenv("BACNET_IFACE");
     if (Datalink_Debug) {
-        fprintf(stderr, "BACNET_IFACE=%s\n", pEnv ? pEnv : "none");
+        debug_fprintf(stderr, "BACNET_IFACE=%s\n", pEnv ? pEnv : "none");
     }
     if (!datalink_init(pEnv)) {
         exit(1);
diff --git a/test/ports/linux/bip_subnet/CMakeLists.txt b/test/ports/linux/bip_subnet/CMakeLists.txt
index c5bc7732..50ab25c5 100644
--- a/test/ports/linux/bip_subnet/CMakeLists.txt
+++ b/test/ports/linux/bip_subnet/CMakeLists.txt
@@ -40,6 +40,7 @@ include_directories(
 
 add_executable(${PROJECT_NAME}
   ${PORTS_DIR}/linux/bip-init.c
+  ${SRC_DIR}/bacnet/basic/sys/debug.c
   ./src/bvlc_stubs.c
   ./src/main.c
   ${ZTST_DIR}/ztest_mock.c