---
 gatchat/gatppp.c |   64 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 gatchat/gatppp.h |    2 +
 2 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/gatchat/gatppp.c b/gatchat/gatppp.c
index c776811..efa909b 100644
--- a/gatchat/gatppp.c
+++ b/gatchat/gatppp.c
@@ -46,6 +46,8 @@
 #define PPP_ADDR_FIELD	0xff
 #define PPP_CTRL	0x03
 
+#define GUARD_TIMEOUTS 1500
+
 enum ppp_phase {
 	PPP_PHASE_DEAD = 0,		/* Link dead */
 	PPP_PHASE_ESTABLISHMENT,	/* LCP started */
@@ -78,6 +80,8 @@ struct _GAtPPP {
 	guint ppp_dead_source;
 	GAtSuspendFunc suspend_func;
 	gpointer suspend_data;
+	guint guard_timeout_src;
+	gboolean suspended;
 };
 
 void ppp_debug(GAtPPP *ppp, const char *str)
@@ -473,6 +477,7 @@ static void ppp_proxy_suspend_net_interface(gpointer user_data)
 {
 	GAtPPP *ppp = user_data;
 
+	ppp->suspended = TRUE;
 	ppp_net_suspend_interface(ppp->net);
 
 	if (ppp->suspend_func)
@@ -500,6 +505,60 @@ void g_at_ppp_shutdown(GAtPPP *ppp)
 	pppcp_signal_close(ppp->lcp);
 }
 
+static gboolean call_suspend_cb(gpointer user_data)
+{
+	GAtPPP *ppp = user_data;
+
+	ppp->guard_timeout_src = 0;
+
+	if (ppp->suspend_func)
+		ppp->suspend_func(ppp->suspend_data);
+
+	return FALSE;
+}
+
+static gboolean send_escape_sequence(gpointer user_data)
+{
+	GAtPPP *ppp = user_data;
+	GAtIO *io = g_at_hdlc_get_io(ppp->hdlc);
+
+	ppp->guard_timeout_src = 0;
+	g_at_io_write(io, "+++", 3);
+	ppp->guard_timeout_src  = g_timeout_add(GUARD_TIMEOUTS,
+						call_suspend_cb, ppp);
+
+	return FALSE;
+}
+
+void g_at_ppp_suspend(GAtPPP *ppp)
+{
+	if (ppp == NULL)
+		return;
+
+	ppp->suspended = TRUE;
+	ppp_net_suspend_interface(ppp->net);
+	g_at_hdlc_suspend(ppp->hdlc);
+	ppp->guard_timeout_src = g_timeout_add(GUARD_TIMEOUTS,
+						send_escape_sequence, ppp);
+}
+
+void g_at_ppp_resume(GAtPPP *ppp)
+{
+	if (ppp == NULL)
+		return;
+
+	if (g_at_hdlc_get_io(ppp->hdlc) == NULL) {
+		io_disconnect(ppp);
+		return;
+	}
+
+	ppp->suspended = FALSE;
+	g_at_io_set_disconnect_function(g_at_hdlc_get_io(ppp->hdlc),
+							io_disconnect, ppp);
+	ppp_net_resume_interface(ppp->net);
+	g_at_hdlc_resume(ppp->hdlc);
+}
+
 void g_at_ppp_ref(GAtPPP *ppp)
 {
 	g_atomic_int_inc(&ppp->ref_count);
@@ -517,8 +576,9 @@ void g_at_ppp_unref(GAtPPP *ppp)
 	if (is_zero == FALSE)
 		return;
 
-	g_at_io_set_disconnect_function(g_at_hdlc_get_io(ppp->hdlc),
-						NULL, NULL);
+	if (ppp->suspended == FALSE)
+		g_at_io_set_disconnect_function(g_at_hdlc_get_io(ppp->hdlc),
+							NULL, NULL);
 
 	if (ppp->net)
 		ppp_net_free(ppp->net);
diff --git a/gatchat/gatppp.h b/gatchat/gatppp.h
index 9464ffd..ab337d7 100644
--- a/gatchat/gatppp.h
+++ b/gatchat/gatppp.h
@@ -64,6 +64,8 @@ void g_at_ppp_set_suspend_function(GAtPPP *ppp, GAtSuspendFunc func,
 					gpointer user_data);
 void g_at_ppp_set_debug(GAtPPP *ppp, GAtDebugFunc func, gpointer user_data);
 void g_at_ppp_shutdown(GAtPPP *ppp);
+void g_at_ppp_suspend(GAtPPP *ppp);
+void g_at_ppp_resume(GAtPPP *ppp);
 void g_at_ppp_ref(GAtPPP *ppp);
 void g_at_ppp_unref(GAtPPP *ppp);
 
-- 
1.7.1