diff --git a/libs/freetdm/src/ftdm_m3ua.c b/libs/freetdm/src/ftdm_m3ua.c
index 31f4cd5c5e..1a6fe362e7 100644
--- a/libs/freetdm/src/ftdm_m3ua.c
+++ b/libs/freetdm/src/ftdm_m3ua.c
@@ -484,7 +484,7 @@ static FIO_SPAN_NEXT_EVENT_FUNCTION(m3ua_next_event)
 
 static FIO_SPAN_DESTROY_FUNCTION(m3ua_span_destroy)
 {
-	m3ua_span_data_t *span_data = (m3ua_span_data_t *) span->mod_data;
+	m3ua_span_data_t *span_data = (m3ua_span_data_t *) span->io_data;
 	
 	if (span_data) {
 		ftdm_safe_free(span_data);
@@ -494,8 +494,8 @@ static FIO_SPAN_DESTROY_FUNCTION(m3ua_span_destroy)
 }
 static FIO_CHANNEL_DESTROY_FUNCTION(m3ua_channel_destroy)
 {
-	m3ua_chan_data_t *chan_data = (m3ua_chan_data_t *) ftdmchan->mod_data;
-	m3ua_span_data_t *span_data = (m3ua_span_data_t *) ftdmchan->span->mod_data;
+	m3ua_chan_data_t *chan_data = (m3ua_chan_data_t *) ftdmchan->io_data;
+	m3ua_span_data_t *span_data = (m3ua_span_data_t *) ftdmchan->span->io_data;
 	
 	if (!chan_data) {
 		return FTDM_FAIL;
diff --git a/libs/freetdm/src/ftmod/ftmod_isdn/ftmod_isdn.c b/libs/freetdm/src/ftmod/ftmod_isdn/ftmod_isdn.c
index 3ccad89828..1dbd6d362e 100644
--- a/libs/freetdm/src/ftmod/ftmod_isdn/ftmod_isdn.c
+++ b/libs/freetdm/src/ftmod/ftmod_isdn/ftmod_isdn.c
@@ -1077,8 +1077,8 @@ static L3INT ftdm_isdn_931_34(void *pvt, struct Q931_Call *call, Q931mes_Generic
 						isdn_data->channels_remote_crv[gen->CRV] = ftdmchan;
 						memset(&ftdmchan->caller_data, 0, sizeof(ftdmchan->caller_data));
 
-						if (ftdmchan->mod_data) {
-							memset(ftdmchan->mod_data, 0, sizeof(ftdm_isdn_bchan_data_t));
+						if (ftdmchan->call_data) {
+							memset(ftdmchan->call_data, 0, sizeof(ftdm_isdn_bchan_data_t));
 						}
 
 						/* copy number readd prefix as needed */
@@ -1210,7 +1210,7 @@ static L3INT ftdm_isdn_931_34(void *pvt, struct Q931_Call *call, Q931mes_Generic
 						 * overlap dial digit indication
 						 */
 						if (Q931IsIEPresent(gen->CalledNum)) {
-							ftdm_isdn_bchan_data_t *data = (ftdm_isdn_bchan_data_t *)ftdmchan->mod_data;
+							ftdm_isdn_bchan_data_t *data = (ftdm_isdn_bchan_data_t *)ftdmchan->call_data;
 							Q931ie_CalledNum *callednum = Q931GetIEPtr(gen->CalledNum, gen->buf);
 							int pos;
 
@@ -1365,7 +1365,7 @@ static __inline__ void state_advance(ftdm_channel_t *ftdmchan)
 		break;
 	case FTDM_CHANNEL_STATE_DIALTONE:
 		{
-			ftdm_isdn_bchan_data_t *data = (ftdm_isdn_bchan_data_t *)ftdmchan->mod_data;
+			ftdm_isdn_bchan_data_t *data = (ftdm_isdn_bchan_data_t *)ftdmchan->call_data;
 
 			if (data) {
 				data->digit_timeout = ftdm_time_now() + isdn_data->digit_timeout;
@@ -1858,7 +1858,7 @@ static void *ftdm_isdn_tones_run(ftdm_thread_t *me, void *obj)
 			switch (ftdm_channel_get_state(chan)) {
 			case FTDM_CHANNEL_STATE_DIALTONE:
 				{
-					ftdm_isdn_bchan_data_t *data = (ftdm_isdn_bchan_data_t *)chan->mod_data;
+					ftdm_isdn_bchan_data_t *data = (ftdm_isdn_bchan_data_t *)chan->call_data;
 					ftdm_caller_data_t *caller_data = ftdm_channel_get_caller_data(chan);
 
 					/* check overlap dial timeout first before generating tone */
@@ -2738,7 +2738,7 @@ static FIO_CONFIGURE_SPAN_SIGNALING_FUNCTION(isdn_configure_span)
 			ftdm_channel_t *chan = ftdm_span_get_channel(span, i);
 
 			if (ftdm_channel_get_type(chan) == FTDM_CHAN_TYPE_B) {
-				chan->mod_data = data;
+				chan->call_data = data;
 				memset(data, 0, sizeof(ftdm_isdn_bchan_data_t));
 			}
 		}
diff --git a/libs/freetdm/src/ftmod/ftmod_pika/ftmod_pika.c b/libs/freetdm/src/ftmod/ftmod_pika/ftmod_pika.c
index f20cbc53a7..aaafdb33cc 100644
--- a/libs/freetdm/src/ftmod/ftmod_pika/ftmod_pika.c
+++ b/libs/freetdm/src/ftmod/ftmod_pika/ftmod_pika.c
@@ -266,7 +266,7 @@ PK_VOID PK_CALLBACK media_out_callback(PKH_TPikaEvent *event)
 {
 	PK_STATUS pk_status;
 	ftdm_channel_t *ftdmchan = event->userData;
-	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->mod_data;
+	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->io_data;
 
 	//PK_CHAR event_text[PKH_EVENT_MAX_NAME_LENGTH];
 	//PKH_EVENT_GetText(event->id, event_text, sizeof(event_text));
@@ -345,8 +345,8 @@ static unsigned pika_open_range(ftdm_span_t *span, unsigned boardno, unsigned sp
 		
 	}
 
-	if (span->mod_data) {
-		span_data = span->mod_data;
+	if (span->io_data) {
+		span_data = span->io_data;
 	} else {
 		span_data = ftdm_malloc(sizeof(*span_data));
 		assert(span_data != NULL);
@@ -364,7 +364,7 @@ static unsigned pika_open_range(ftdm_span_t *span, unsigned boardno, unsigned sp
 
 		//PKH_QUEUE_Attach(span_data->event_queue, globals.open_boards[boardno], NULL);
 
-		span->mod_data = span_data;
+		span->io_data = span_data;
 	}
 
 	if (type == FTDM_CHAN_TYPE_FXS || type == FTDM_CHAN_TYPE_FXO) {
@@ -380,7 +380,7 @@ static unsigned pika_open_range(ftdm_span_t *span, unsigned boardno, unsigned sp
 		assert(chan_data);
 		memset(chan_data, 0, sizeof(*chan_data));
 		ftdm_span_add_channel(span, 0, type, &chan);
-		chan->mod_data = chan_data;
+		chan->io_data = chan_data;
 
 		if ((type == FTDM_CHAN_TYPE_B || type == FTDM_CHAN_TYPE_DQ921) && !span_data->handle) {
 			PKH_TBoardConfig boardConfig;
@@ -680,7 +680,7 @@ static FIO_CONFIGURE_SPAN_FUNCTION(pika_configure_span)
  */
 static FIO_OPEN_FUNCTION(pika_open) 
 {
-	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->mod_data;
+	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->io_data;
 
 	if (!chan_data && !ftdm_test_flag(chan_data, PK_FLAG_READY)) {
 		return FTDM_FAIL;
@@ -715,7 +715,7 @@ static FIO_CLOSE_FUNCTION(pika_close)
  */
 static FIO_WAIT_FUNCTION(pika_wait)
 {
-	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->mod_data;
+	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->io_data;
 	PK_STATUS status;
 	ftdm_wait_flag_t myflags = *flags;
 	PK_CHAR event_text[PKH_EVENT_MAX_NAME_LENGTH];
@@ -754,7 +754,7 @@ static FIO_WAIT_FUNCTION(pika_wait)
  */
 static FIO_READ_FUNCTION(pika_read)
 {
-	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->mod_data;
+	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->io_data;
 	PK_STATUS status;
 	PK_CHAR event_text[PKH_EVENT_MAX_NAME_LENGTH];
 	uint32_t len;
@@ -795,7 +795,7 @@ static FIO_READ_FUNCTION(pika_read)
  */
 static FIO_WRITE_FUNCTION(pika_write)
 {
-	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->mod_data;
+	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->io_data;
 	PK_STATUS status;
 
 	if (ftdmchan->type == FTDM_CHAN_TYPE_DQ921) {
@@ -821,8 +821,8 @@ static FIO_WRITE_FUNCTION(pika_write)
  */
 static FIO_COMMAND_FUNCTION(pika_command)
 {
-	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->mod_data;
-	//pika_span_data_t *span_data = (pika_span_data_t *) ftdmchan->span->mod_data;
+	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->io_data;
+	//pika_span_data_t *span_data = (pika_span_data_t *) ftdmchan->span->io_data;
 	PK_STATUS pk_status;
 	ftdm_status_t status = FTDM_SUCCESS;
 
@@ -956,7 +956,7 @@ static FIO_COMMAND_FUNCTION(pika_command)
  */
 static FIO_SPAN_POLL_EVENT_FUNCTION(pika_poll_event)
 {
-	pika_span_data_t *span_data = (pika_span_data_t *) span->mod_data;
+	pika_span_data_t *span_data = (pika_span_data_t *) span->io_data;
 	PK_STATUS status;
 	PK_CHAR event_text[PKH_EVENT_MAX_NAME_LENGTH];
 
@@ -1025,7 +1025,7 @@ static FIO_SPAN_POLL_EVENT_FUNCTION(pika_poll_event)
 				for(x = 1; x <= span->chan_count; x++) {
 					ftdmchan = span->channels[x];
 					assert(ftdmchan != NULL);
-					chan_data = (pika_chan_data_t *) ftdmchan->mod_data;
+					chan_data = (pika_chan_data_t *) ftdmchan->io_data;
 					assert(chan_data != NULL);
 					
 
@@ -1042,7 +1042,7 @@ static FIO_SPAN_POLL_EVENT_FUNCTION(pika_poll_event)
 		//ftdm_log(FTDM_LOG_DEBUG, "Event: %s\n", event_text);
 		
 		if (ftdmchan) {
-			pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->mod_data;
+			pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->io_data;
 
 			assert(chan_data != NULL);
 			ftdm_set_flag(ftdmchan, FTDM_CHANNEL_EVENT);
@@ -1068,7 +1068,7 @@ static FIO_SPAN_NEXT_EVENT_FUNCTION(pika_next_event)
 	
 	for(i = 1; i <= span->chan_count; i++) {
 		if (ftdm_test_flag(span->channels[i], FTDM_CHANNEL_EVENT)) {
-			pika_chan_data_t *chan_data = (pika_chan_data_t *) span->channels[i]->mod_data;
+			pika_chan_data_t *chan_data = (pika_chan_data_t *) span->channels[i]->io_data;
 			PK_CHAR event_text[PKH_EVENT_MAX_NAME_LENGTH];
 			
 			ftdm_clear_flag(span->channels[i], FTDM_CHANNEL_EVENT);
@@ -1207,7 +1207,7 @@ static FIO_SPAN_NEXT_EVENT_FUNCTION(pika_next_event)
  */
 static FIO_SPAN_DESTROY_FUNCTION(pika_span_destroy)
 {
-	pika_span_data_t *span_data = (pika_span_data_t *) span->mod_data;
+	pika_span_data_t *span_data = (pika_span_data_t *) span->io_data;
 	
 	if (span_data) {
 		PKH_QUEUE_Destroy(span_data->event_queue);
@@ -1224,8 +1224,8 @@ static FIO_SPAN_DESTROY_FUNCTION(pika_span_destroy)
  */
 static FIO_CHANNEL_DESTROY_FUNCTION(pika_channel_destroy)
 {
-	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->mod_data;
-	pika_span_data_t *span_data = (pika_span_data_t *) ftdmchan->span->mod_data;
+	pika_chan_data_t *chan_data = (pika_chan_data_t *) ftdmchan->io_data;
+	pika_span_data_t *span_data = (pika_span_data_t *) ftdmchan->span->io_data;
 	
 	if (!chan_data) {
 		return FTDM_FAIL;
diff --git a/libs/freetdm/src/ftmod/ftmod_wanpipe/ftmod_wanpipe.c b/libs/freetdm/src/ftmod/ftmod_wanpipe/ftmod_wanpipe.c
index 896b8eebd8..8e8acc24e3 100644
--- a/libs/freetdm/src/ftmod/ftmod_wanpipe/ftmod_wanpipe.c
+++ b/libs/freetdm/src/ftmod/ftmod_wanpipe/ftmod_wanpipe.c
@@ -117,28 +117,28 @@ static __inline__ int tdmv_api_wait_socket(ftdm_channel_t *ftdmchan, int timeout
 	
 #ifdef LIBSANGOMA_VERSION
 	int err;
-    uint32_t inflags = *flags;
-    uint32_t outflags = 0;
-	sangoma_wait_obj_t *sangoma_wait_obj = ftdmchan->mod_data;
+	uint32_t inflags = *flags;
+	uint32_t outflags = 0;
+	sangoma_wait_obj_t *sangoma_wait_obj = ftdmchan->io_data;
 
 	err = sangoma_waitfor(sangoma_wait_obj, inflags, &outflags, timeout);
 	*flags = 0;
-    if (err == SANG_STATUS_SUCCESS) {
-        *flags = outflags;
-        err = 1; /* ideally should be the number of file descriptors with something to read */
-    }
-    if (err == SANG_STATUS_APIPOLL_TIMEOUT) {
-        err = 0;
-    }
-    return err;
+	if (err == SANG_STATUS_SUCCESS) {
+        	*flags = outflags;
+        	err = 1; /* ideally should be the number of file descriptors with something to read */
+	}
+	if (err == SANG_STATUS_APIPOLL_TIMEOUT) {
+		err = 0;
+	}
+	return err;
 #else
  	struct pollfd pfds[1];
-    int res;
+	int res;
 
-    memset(&pfds[0], 0, sizeof(pfds[0]));
-    pfds[0].fd = ftdmchan->sockfd;
-    pfds[0].events = *flags;
-    res = poll(pfds, 1, timeout);
+	memset(&pfds[0], 0, sizeof(pfds[0]));
+	pfds[0].fd = ftdmchan->sockfd;
+	pfds[0].events = *flags;
+	res = poll(pfds, 1, timeout);
 	*flags = 0;
 
 	if (pfds[0].revents & POLLERR) {
@@ -149,7 +149,7 @@ static __inline__ int tdmv_api_wait_socket(ftdm_channel_t *ftdmchan, int timeout
 		*flags = pfds[0].revents;
 	}
 
-    return res;
+	return res;
 #endif
 	
 }
@@ -252,7 +252,7 @@ static unsigned wp_open_range(ftdm_span_t *span, unsigned spanno, unsigned start
 				ftdm_log(FTDM_LOG_ERROR, "failure create waitable object for s%dc%d\n", spanno, x);
 				continue;
 			}
-			chan->mod_data = sangoma_wait_obj;
+			chan->io_data = sangoma_wait_obj;
 #endif
 			
 			chan->physical_span_id = spanno;
@@ -541,7 +541,7 @@ static FIO_OPEN_FUNCTION(wanpipe_open)
 static FIO_CLOSE_FUNCTION(wanpipe_close)
 {
 #ifdef LIBSANGOMA_VERSION
-	sangoma_wait_obj_t *waitobj = ftdmchan->mod_data;
+	sangoma_wait_obj_t *waitobj = ftdmchan->io_data;
 	/* kick any I/O waiters */
 	sangoma_wait_obj_signal(waitobj);
 #endif
@@ -895,10 +895,10 @@ FIO_SPAN_POLL_EVENT_FUNCTION(wanpipe_poll_event)
 	for(i = 1; i <= span->chan_count; i++) {
 		ftdm_channel_t *ftdmchan = span->channels[i];
 #ifdef LIBSANGOMA_VERSION
-		if (!ftdmchan->mod_data) {
+		if (!ftdmchan->io_data) {
 			continue; /* should never happen but happens when shutting down */
 		}
-		pfds[j] = ftdmchan->mod_data;
+		pfds[j] = ftdmchan->io_data;
 		inflags[j] = poll_events ? poll_events[j] : POLLPRI;
 #else
 		memset(&pfds[j], 0, sizeof(pfds[j]));
@@ -1234,10 +1234,10 @@ FIO_SPAN_NEXT_EVENT_FUNCTION(wanpipe_next_event)
 static FIO_CHANNEL_DESTROY_FUNCTION(wanpipe_channel_destroy)
 {
 #ifdef LIBSANGOMA_VERSION
-	if (ftdmchan->mod_data) {
+	if (ftdmchan->io_data) {
 		sangoma_wait_obj_t *sangoma_wait_obj;
-		sangoma_wait_obj = ftdmchan->mod_data;
-		ftdmchan->mod_data = NULL;
+		sangoma_wait_obj = ftdmchan->io_data;
+		ftdmchan->io_data = NULL;
 		sangoma_wait_obj_delete(&sangoma_wait_obj);
 	}
 #endif
diff --git a/libs/freetdm/src/include/private/ftdm_core.h b/libs/freetdm/src/include/private/ftdm_core.h
index dbf108020b..ab20ef8171 100644
--- a/libs/freetdm/src/include/private/ftdm_core.h
+++ b/libs/freetdm/src/include/private/ftdm_core.h
@@ -424,7 +424,9 @@ struct ftdm_channel {
 	ftdm_fsk_data_state_t fsk;
 	uint8_t fsk_buf[80];
 	uint32_t ring_count;
-	void *mod_data;
+	/* Private I/O data. Do not touch unless you are an I/O module */
+	void *io_data;
+	/* Private signaling data. Do not touch unless you are a signaling module */
 	void *call_data;
 	struct ftdm_caller_data caller_data;
 	struct ftdm_span *span;
@@ -456,6 +458,7 @@ struct ftdm_span {
 	ftdm_trunk_type_t trunk_type;
 	ftdm_analog_start_type_t start_type;
 	ftdm_signal_type_t signal_type;
+	/* Private signaling data. Do not touch unless you are a signaling module */
 	void *signal_data;
 	fio_signal_cb_t signal_cb;
 	ftdm_event_t event_header;
@@ -473,7 +476,8 @@ struct ftdm_span {
 	ftdm_span_start_t start;
 	ftdm_span_stop_t stop;
 	ftdm_channel_sig_read_t sig_read;
-	void *mod_data;
+	/* Private I/O data per span. Do not touch unless you are an I/O module */
+	void *io_data;
 	char *type;
 	char *dtmf_hangup;
 	size_t dtmf_hangup_len;