diff -ur a/plugins/huawei/mm-broadband-bearer-huawei.c b/plugins/huawei/mm-broadband-bearer-huawei.c
--- a/plugins/huawei/mm-broadband-bearer-huawei.c
+++ b/plugins/huawei/mm-broadband-bearer-huawei.c
@@ -256,13 +259,26 @@
         user = mm_bearer_properties_get_user (mm_bearer_peek_config (MM_BEARER (ctx->self)));
         passwd = mm_bearer_properties_get_password (mm_bearer_peek_config (MM_BEARER (ctx->self)));
         auth = mm_bearer_properties_get_allowed_auth (mm_bearer_peek_config (MM_BEARER (ctx->self)));
-        encoded_auth = huawei_parse_auth_type (auth);
+        
+        /* Default to no authentication if not specified */
+        if ((encoded_auth = huawei_parse_auth_type (auth)) == MM_BEARER_HUAWEI_AUTH_UNKNOWN) {
+            encoded_auth = MM_BEARER_HUAWEI_AUTH_NONE;
+        }
 
-        command = g_strdup_printf ("AT^NDISDUP=1,1,\"%s\",\"%s\",\"%s\",%d",
-                                   apn == NULL ? "" : apn,
-                                   user == NULL ? "" : user,
-                                   passwd == NULL ? "" : passwd,
-                                   encoded_auth == MM_BEARER_HUAWEI_AUTH_UNKNOWN ? MM_BEARER_HUAWEI_AUTH_NONE : encoded_auth);
+        if (!user && !passwd) {
+            command = g_strdup ("AT^NDISDUP=1,1");
+        } else if (encoded_auth == MM_BEARER_HUAWEI_AUTH_NONE) {
+		    command = g_strdup_printf ("AT^NDISDUP=1,1,\"%s\",\"%s\",\"%s\"",
+                                       apn == NULL ? "" : apn,
+                                       user == NULL ? "" : user,
+                                       passwd == NULL ? "" : passwd);
+        } else {			
+            command = g_strdup_printf ("AT^NDISDUP=1,1,\"%s\",\"%s\",\"%s\",%d",
+                                       apn == NULL ? "" : apn,
+                                       user == NULL ? "" : user,
+                                       passwd == NULL ? "" : passwd,
+                                       encoded_auth);
+        }
         mm_base_modem_at_command_full (ctx->modem,
                                        ctx->primary,
                                        command,