diff --git a/drivers/stemodem/voicecall.c b/drivers/stemodem/voicecall.c
index db3b7219..aa5a071a 100644
--- a/drivers/stemodem/voicecall.c
+++ b/drivers/stemodem/voicecall.c
@@ -533,6 +533,16 @@ static void ecav_notify(GAtResult *result, gpointer user_data)
 	}
 }
 
+static void ste_voicecall_initialized(gboolean ok, GAtResult *result,
+					gpointer user_data)
+{
+	struct ofono_voicecall *vc = user_data;
+	struct voicecall_data *vd = ofono_voicecall_get_data(vc);
+
+	g_at_chat_register(vd->chat, "*ECAV:", ecav_notify, FALSE, vc, NULL);
+	ofono_voicecall_register(vc);
+}
+
 static int ste_voicecall_probe(struct ofono_voicecall *vc, unsigned int vendor,
 				void *data)
 {
@@ -544,9 +554,8 @@ static int ste_voicecall_probe(struct ofono_voicecall *vc, unsigned int vendor,
 
 	ofono_voicecall_set_data(vc, vd);
 
-	g_at_chat_send(vd->chat, "AT*ECAM=1", NULL, NULL, NULL, NULL);
-	g_at_chat_register(vd->chat, "*ECAV:", ecav_notify, FALSE, vc, NULL);
-	ofono_voicecall_register(vc);
+	g_at_chat_send(vd->chat, "AT*ECAM=1", none_prefix,
+			ste_voicecall_initialized, vc, NULL);
 
 	return 0;
 }