diff --git a/gatchat/gatppp.c b/gatchat/gatppp.c
index 556387ae..fc845492 100644
--- a/gatchat/gatppp.c
+++ b/gatchat/gatppp.c
@@ -44,13 +44,13 @@ void g_at_ppp_open(GAtPPP *ppp)
 }
 
 void g_at_ppp_set_credentials(GAtPPP *ppp, const char *username,
-				const char *passwd)
+							const char *passwd)
 {
 	auth_set_credentials(ppp->auth, username, passwd);
 }
 
 void g_at_ppp_set_connect_function(GAtPPP *ppp, GAtPPPConnectFunc func,
-					gpointer user_data)
+							gpointer user_data)
 {
 	if (func == NULL)
 		return;
@@ -60,7 +60,7 @@ void g_at_ppp_set_connect_function(GAtPPP *ppp, GAtPPPConnectFunc func,
 }
 
 void g_at_ppp_set_disconnect_function(GAtPPP *ppp, GAtDisconnectFunc func,
-					  gpointer user_data)
+							gpointer user_data)
 {
 	if (func == NULL)
 		return;
@@ -69,6 +69,15 @@ void g_at_ppp_set_disconnect_function(GAtPPP *ppp, GAtDisconnectFunc func,
 	ppp->disconnect_data = user_data;
 }
 
+void g_at_ppp_set_debug(GAtPPP *ppp, GAtDebugFunc func, gpointer user_data)
+{
+	if (ppp == NULL)
+		return;
+
+	ppp->debugf = func;
+	ppp->debug_data = user_data;
+}
+
 void g_at_ppp_shutdown(GAtPPP *ppp)
 {
 	/* close the ppp link */
diff --git a/gatchat/gatppp.h b/gatchat/gatppp.h
index b37f74d5..3d1f74e7 100644
--- a/gatchat/gatppp.h
+++ b/gatchat/gatppp.h
@@ -47,6 +47,7 @@ void g_at_ppp_set_connect_function(GAtPPP *ppp, GAtPPPConnectFunc callback,
 					gpointer user_data);
 void g_at_ppp_set_disconnect_function(GAtPPP *ppp, GAtDisconnectFunc 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_ref(GAtPPP *ppp);
 void g_at_ppp_unref(GAtPPP *ppp);
diff --git a/gatchat/gsmdial.c b/gatchat/gsmdial.c
index 1050bd6c..d15aaa91 100644
--- a/gatchat/gsmdial.c
+++ b/gatchat/gsmdial.c
@@ -71,7 +71,7 @@ static int oldmode = 0;
 
 static void gsmdial_debug(const char *str, void *data)
 {
-	g_print("%s: %s\n", (const char *)data, str);
+	g_print("%s: %s\n", (const char *) data, str);
 }
 
 static gboolean quit_eventloop(gpointer user_data)
@@ -269,8 +269,9 @@ static void connect_cb(gboolean ok, GAtResult *result, gpointer user_data)
 		g_print("Unable to create PPP object\n");
 		exit(1);
 	}
-	g_at_ppp_set_credentials(ppp, option_username,
-				option_password);
+	g_at_ppp_set_debug(ppp, gsmdial_debug, "PPP");
+
+	g_at_ppp_set_credentials(ppp, option_username, option_password);
 
 	/* set connect and disconnect callbacks */
 	g_at_ppp_set_connect_function(ppp, ppp_connect, NULL);
diff --git a/gatchat/ppp.h b/gatchat/ppp.h
index b8d51ece..bf1f5508 100644
--- a/gatchat/ppp.h
+++ b/gatchat/ppp.h
@@ -137,6 +137,8 @@ struct _GAtPPP {
 	GAtDisconnectFunc disconnect_cb;
 	gpointer disconnect_data;
 	gint modem_watch;
+	GAtDebugFunc debugf;
+	gpointer debug_data;
 };
 
 gboolean ppp_cb(GIOChannel *channel, GIOCondition cond, gpointer data);
diff --git a/gatchat/ppp_cp.c b/gatchat/ppp_cp.c
index 82e5b10b..a0461e33 100644
--- a/gatchat/ppp_cp.c
+++ b/gatchat/ppp_cp.c
@@ -34,19 +34,25 @@
 #include "gatppp.h"
 #include "ppp.h"
 
-#define DEBUG
-#ifdef DEBUG
 static const char *pppcp_state_strings[] =
 	{"INITIAL", "STARTING", "CLOSED", "STOPPED", "CLOSING", "STOPPING",
 	"REQSENT", "ACKRCVD", "ACKSENT", "OPENED" };
 
-#define pppcp_trace(p) do { \
-	g_print("%s: %s: current state %d:%s\n", p->prefix, __FUNCTION__, \
-		p->state, pppcp_state_strings[p->state]); \
-} while (0)
-#else
-#define pppcp_trace(p) do { } while (0)
-#endif
+static void pppcp_debug(struct pppcp_data *p, const char *func)
+{
+	GAtPPP *ppp = p->ppp;
+	char *str;
+
+	if (!ppp || !ppp->debugf)
+		return;
+
+	str = g_strdup_printf("%s: %s: current state %d:%s",
+		p->prefix, func, p->state, pppcp_state_strings[p->state]);
+	ppp->debugf(str, ppp->debug_data);
+	g_free(str);
+}
+
+#define pppcp_trace(p) pppcp_debug(p, __FUNCTION__)
 
 #define pppcp_to_ppp_packet(p) \
 	(((guint8 *) p) - PPP_HEADROOM)