diff --git a/libs/freetdm/src/ftdm_io.c b/libs/freetdm/src/ftdm_io.c
index ab015b98ff..4b49a9156c 100644
--- a/libs/freetdm/src/ftdm_io.c
+++ b/libs/freetdm/src/ftdm_io.c
@@ -262,9 +262,12 @@ FTDM_STR2ENUM(ftdm_str2ftdm_tonemap, ftdm_tonemap2str, ftdm_tonemap_t, TONEMAP_N
 FTDM_ENUM_NAMES(OOB_NAMES, OOB_STRINGS)
 FTDM_STR2ENUM(ftdm_str2ftdm_oob_event, ftdm_oob_event2str, ftdm_oob_event_t, OOB_NAMES, FTDM_OOB_INVALID)
 
-FTDM_ENUM_NAMES(TRUNK_TYPE_NAMES, TRUNK_STRINGS)
+FTDM_ENUM_NAMES(TRUNK_TYPE_NAMES, TRUNK_TYPE_STRINGS)
 FTDM_STR2ENUM(ftdm_str2ftdm_trunk_type, ftdm_trunk_type2str, ftdm_trunk_type_t, TRUNK_TYPE_NAMES, FTDM_TRUNK_NONE)
 
+FTDM_ENUM_NAMES(TRUNK_MODE_NAMES, TRUNK_MODE_STRINGS)
+FTDM_STR2ENUM(ftdm_str2ftdm_trunk_mode, ftdm_trunk_mode2str, ftdm_trunk_mode_t, TRUNK_MODE_NAMES, FTDM_TRUNK_MODE_INVALID)
+
 FTDM_ENUM_NAMES(START_TYPE_NAMES, START_TYPE_STRINGS)
 FTDM_STR2ENUM(ftdm_str2ftdm_analog_start_type, ftdm_analog_start_type2str, ftdm_analog_start_type_t, START_TYPE_NAMES, FTDM_ANALOG_START_NA)
 
@@ -816,6 +819,7 @@ FT_DECLARE(ftdm_status_t) ftdm_span_create(const char *iotype, const char *name,
 		ftdm_copy_string(new_span->tone_map[FTDM_TONEMAP_BUSY], "%(500,500,480,620)", FTDM_TONEMAP_LEN);
 		ftdm_copy_string(new_span->tone_map[FTDM_TONEMAP_ATTN], "%(100,100,1400,2060,2450,2600)", FTDM_TONEMAP_LEN);
 		new_span->trunk_type = FTDM_TRUNK_NONE;
+		new_span->trunk_mode = FTDM_TRUNK_MODE_CPE;
 		new_span->data_type = FTDM_TYPE_SPAN;
 
 		ftdm_mutex_lock(globals.span_mutex);
@@ -1994,6 +1998,21 @@ FT_DECLARE(const char *) ftdm_span_get_trunk_type_str(const ftdm_span_t *span)
 	return ftdm_trunk_type2str(span->trunk_type);
 }
 
+FT_DECLARE(void) ftdm_span_set_trunk_mode(ftdm_span_t *span, ftdm_trunk_mode_t mode)
+{
+	span->trunk_mode = mode;
+}
+
+FT_DECLARE(ftdm_trunk_mode_t) ftdm_span_get_trunk_mode(const ftdm_span_t *span)
+{
+	return span->trunk_mode;
+}
+
+FT_DECLARE(const char *) ftdm_span_get_trunk_mode_str(const ftdm_span_t *span)
+{
+	return ftdm_trunk_mode2str(span->trunk_mode);
+}
+
 FT_DECLARE(uint32_t) ftdm_span_get_id(const ftdm_span_t *span)
 {
 	return span->span_id;
@@ -4706,6 +4725,10 @@ static ftdm_status_t load_config(void)
 				ftdm_trunk_type_t trtype = ftdm_str2ftdm_trunk_type(val);
 				ftdm_span_set_trunk_type(span, trtype);
 				ftdm_log(FTDM_LOG_DEBUG, "setting trunk type to '%s'\n", ftdm_trunk_type2str(trtype)); 
+			} else if (!strcasecmp(var, "trunk_mode")) {
+				ftdm_trunk_mode_t trmode = ftdm_str2ftdm_trunk_mode(val);
+				ftdm_span_set_trunk_mode(span, trmode);
+				ftdm_log(FTDM_LOG_DEBUG, "setting trunk mode to '%s'\n", ftdm_trunk_mode2str(trmode));
 			} else if (!strcasecmp(var, "name")) {
 				if (!strcasecmp(val, "undef")) {
 					chan_config.name[0] = '\0';
@@ -4729,9 +4752,10 @@ static ftdm_status_t load_config(void)
 				}
 			} else if (!strcasecmp(var, "fxo-channel")) {
 				if (span->trunk_type == FTDM_TRUNK_NONE) {
-					span->trunk_type = FTDM_TRUNK_FXO;										
-					ftdm_log(FTDM_LOG_DEBUG, "setting trunk type to '%s' start(%s)\n", ftdm_trunk_type2str(span->trunk_type), 
-							ftdm_analog_start_type2str(span->start_type));
+					span->trunk_type = FTDM_TRUNK_FXO;
+					span->trunk_mode = FTDM_TRUNK_MODE_CPE;
+					ftdm_log(FTDM_LOG_DEBUG, "setting trunk type to '%s' start(%s), mode(%s)\n", ftdm_trunk_type2str(span->trunk_type),
+							ftdm_analog_start_type2str(span->start_type), ftdm_trunk_mode2str(span->trunk_mode));
 				}
 				if (span->trunk_type == FTDM_TRUNK_FXO) {
 					unsigned chans_configured = 0;
@@ -4745,8 +4769,9 @@ static ftdm_status_t load_config(void)
 			} else if (!strcasecmp(var, "fxs-channel")) {
 				if (span->trunk_type == FTDM_TRUNK_NONE) {
 					span->trunk_type = FTDM_TRUNK_FXS;
-					ftdm_log(FTDM_LOG_DEBUG, "setting trunk type to '%s' start(%s)\n", ftdm_trunk_type2str(span->trunk_type), 
-							ftdm_analog_start_type2str(span->start_type));
+					span->trunk_mode = FTDM_TRUNK_MODE_NET;
+					ftdm_log(FTDM_LOG_DEBUG, "setting trunk type to '%s' start(%s), mode(%s)\n", ftdm_trunk_type2str(span->trunk_type),
+							ftdm_analog_start_type2str(span->start_type), ftdm_trunk_mode2str(span->trunk_mode));
 				}
 				if (span->trunk_type == FTDM_TRUNK_FXS) {
 					unsigned chans_configured = 0;
@@ -4760,8 +4785,9 @@ static ftdm_status_t load_config(void)
 			} else if (!strcasecmp(var, "em-channel")) {
 				if (span->trunk_type == FTDM_TRUNK_NONE) {
 					span->trunk_type = FTDM_TRUNK_EM;
-					ftdm_log(FTDM_LOG_DEBUG, "setting trunk type to '%s' start(%s)\n", ftdm_trunk_type2str(span->trunk_type), 
-							ftdm_analog_start_type2str(span->start_type));
+					span->trunk_mode = FTDM_TRUNK_MODE_CPE;
+					ftdm_log(FTDM_LOG_DEBUG, "setting trunk type to '%s' start(%s), mode(%s)\n", ftdm_trunk_type2str(span->trunk_type),
+							ftdm_analog_start_type2str(span->start_type), ftdm_trunk_mode2str(span->trunk_mode));
 				}
 				if (span->trunk_type == FTDM_TRUNK_EM) {
 					unsigned chans_configured = 0;
diff --git a/libs/freetdm/src/ftmod/ftmod_libpri/ftmod_libpri.c b/libs/freetdm/src/ftmod/ftmod_libpri/ftmod_libpri.c
index ecd1cff1d3..471b870f34 100644
--- a/libs/freetdm/src/ftmod/ftmod_libpri/ftmod_libpri.c
+++ b/libs/freetdm/src/ftmod/ftmod_libpri/ftmod_libpri.c
@@ -2462,9 +2462,15 @@ static FIO_CONFIGURE_SPAN_SIGNALING_FUNCTION(ftdm_libpri_configure_span)
 	memset(isdn_data, 0, sizeof(*isdn_data));
 
 	/* set some default values */
-	isdn_data->mode = PRI_CPE;
 	isdn_data->ton  = PRI_UNKNOWN;
 
+	/* Use span's trunk_mode as a reference for the default libpri mode */
+	if (ftdm_span_get_trunk_mode(span) == FTDM_TRUNK_MODE_NET) {
+		isdn_data->mode = PRI_NETWORK;
+	} else {
+		isdn_data->mode = PRI_CPE;
+	}
+
 	switch (ftdm_span_get_trunk_type(span)) {
 	case FTDM_TRUNK_BRI:
 	case FTDM_TRUNK_BRI_PTMP:
@@ -2516,8 +2522,8 @@ static FIO_CONFIGURE_SPAN_SIGNALING_FUNCTION(ftdm_libpri_configure_span)
 
 		if (!strcasecmp(var, "node") || !strcasecmp(var, "mode")) {
 			if ((isdn_data->mode = parse_mode(val)) == -1) {
-				ftdm_log(FTDM_LOG_ERROR, "Unknown node type '%s', defaulting to CPE mode\n", val);
-				isdn_data->mode = PRI_CPE;
+				ftdm_log(FTDM_LOG_ERROR, "Unknown node type '%s'\n", val);
+				goto error;
 			}
 		}
 		else if (!strcasecmp(var, "switch") || !strcasecmp(var, "dialect")) {
@@ -2563,6 +2569,16 @@ static FIO_CONFIGURE_SPAN_SIGNALING_FUNCTION(ftdm_libpri_configure_span)
 		}
 	}
 
+	/* Check if modes match and log a message if they do not. Just to be on the safe side. */
+	if (isdn_data->mode == PRI_CPE && ftdm_span_get_trunk_mode(span) == FTDM_TRUNK_MODE_NET) {
+		ftdm_log(FTDM_LOG_WARNING, "Span '%s' signalling set up for TE/CPE/USER mode, while port is running in NT/NET mode. You may want to check your 'trunk_mode' settings.\n",
+			ftdm_span_get_name(span));
+	}
+	else if (isdn_data->mode == PRI_NETWORK && ftdm_span_get_trunk_mode(span) == FTDM_TRUNK_MODE_CPE) {
+		ftdm_log(FTDM_LOG_WARNING, "Span '%s' signalling set up for NT/NET mode, while port is running in TE/CPE/USER mode. You may want to check your 'trunk_mode' settings.\n",
+			ftdm_span_get_name(span));
+	}
+
 	span->start = ftdm_libpri_start;
 	span->stop  = ftdm_libpri_stop;
 	span->signal_cb = sig_cb;
diff --git a/libs/freetdm/src/ftmod/ftmod_misdn/ftmod_misdn.c b/libs/freetdm/src/ftmod/ftmod_misdn/ftmod_misdn.c
index 60e3c1425d..c304a8b37b 100644
--- a/libs/freetdm/src/ftmod/ftmod_misdn/ftmod_misdn.c
+++ b/libs/freetdm/src/ftmod/ftmod_misdn/ftmod_misdn.c
@@ -1432,12 +1432,12 @@ static ftdm_status_t misdn_open_range(ftdm_span_t *span, ftdm_chan_type_t type,
 
 	switch (ftdm_span_get_trunk_type(span)) {
 	case FTDM_TRUNK_E1:
-		d_protocol = ISDN_P_TE_E1;
+		d_protocol = ftdm_span_get_trunk_mode(span) == FTDM_TRUNK_MODE_NET ? ISDN_P_NT_E1 : ISDN_P_TE_E1;
 		d_channel  = 16;
 		break;
 	case FTDM_TRUNK_BRI:
 	case FTDM_TRUNK_BRI_PTMP:
-		d_protocol = ISDN_P_TE_S0;
+		d_protocol = ftdm_span_get_trunk_mode(span) == FTDM_TRUNK_MODE_NET ? ISDN_P_NT_S0 : ISDN_P_TE_S0;
 		d_channel  = 0;
 		break;
 	default:
diff --git a/libs/freetdm/src/include/freetdm.h b/libs/freetdm/src/include/freetdm.h
index d984f5b1c8..809465c47a 100755
--- a/libs/freetdm/src/include/freetdm.h
+++ b/libs/freetdm/src/include/freetdm.h
@@ -484,11 +484,23 @@ typedef enum {
 	FTDM_TRUNK_GSM,
 	FTDM_TRUNK_NONE
 } ftdm_trunk_type_t;
-#define TRUNK_STRINGS "E1", "T1", "J1", "BRI", "BRI_PTMP", "FXO", "FXS", "EM", "GSM", "NONE"
+#define TRUNK_TYPE_STRINGS "E1", "T1", "J1", "BRI", "BRI_PTMP", "FXO", "FXS", "EM", "GSM", "NONE"
 
 /*! \brief Move from string to ftdm_trunk_type_t and viceversa */
 FTDM_STR2ENUM_P(ftdm_str2ftdm_trunk_type, ftdm_trunk_type2str, ftdm_trunk_type_t)
 
+/*! \brief Span trunk modes */
+typedef enum {
+	FTDM_TRUNK_MODE_CPE,
+	FTDM_TRUNK_MODE_NET,
+	FTDM_TRUNK_MODE_INVALID
+} ftdm_trunk_mode_t;
+#define TRUNK_MODE_STRINGS "CPE", "NET", "INVALID"
+
+/*! \brief Move from string to ftdm_trunk_mode_t and viceversa */
+FTDM_STR2ENUM_P(ftdm_str2ftdm_trunk_mode, ftdm_trunk_mode2str, ftdm_trunk_mode_t)
+
+
 /*! \brief Basic channel configuration provided to ftdm_configure_span_channels */
 typedef struct ftdm_channel_config {
 	char name[FTDM_MAX_NAME_STR_SZ];
@@ -1744,6 +1756,28 @@ FT_DECLARE(ftdm_trunk_type_t) ftdm_span_get_trunk_type(const ftdm_span_t *span);
 /*! \brief For display debugging purposes you can display this string which describes the trunk type of a span */
 FT_DECLARE(const char *) ftdm_span_get_trunk_type_str(const ftdm_span_t *span);
 
+/*!
+ * Set the trunk mode for a span
+ * \note	This must be called before configuring any channels within the span!
+ * \param[in]	span	The span
+ * \param[in]	type	The trunk mode
+ */
+FT_DECLARE(void) ftdm_span_set_trunk_mode(ftdm_span_t *span, ftdm_trunk_mode_t mode);
+
+/*!
+ * Get the trunk mode for a span
+ * \param[in]	span	The span
+ * \return	Span trunk mode
+ */
+FT_DECLARE(ftdm_trunk_mode_t) ftdm_span_get_trunk_mode(const ftdm_span_t *span);
+
+/*!
+ * Get the trunk mode of a span in textual form
+ * \param[in]	span	The span
+ * \return	Span mode name as a string
+ */
+FT_DECLARE(const char *) ftdm_span_get_trunk_mode_str(const ftdm_span_t *span);
+
 /*! 
  * \brief Return the channel identified by the provided id
  *
diff --git a/libs/freetdm/src/include/private/ftdm_core.h b/libs/freetdm/src/include/private/ftdm_core.h
index 7cd8aacafb..fa1bd233cd 100644
--- a/libs/freetdm/src/include/private/ftdm_core.h
+++ b/libs/freetdm/src/include/private/ftdm_core.h
@@ -485,6 +485,7 @@ struct ftdm_span {
 	fio_event_cb_t event_callback;
 	ftdm_mutex_t *mutex;
 	ftdm_trunk_type_t trunk_type;
+	ftdm_trunk_mode_t trunk_mode;
 	ftdm_analog_start_type_t start_type;
 	ftdm_signal_type_t signal_type;
 	uint32_t last_used_index;