If an Attendant DN is configured on FXO port and this parameter is set to True, then Callmanager will limit outbound calls from that DN to only use the FXO port that is configured with that Attendant DN. You would need to create a route pattern and include this FXO port in the route list. Even though there are other gateways that could be listed above in the route list, it would still use this gateway only.
Also, none of the other phones will be able to use this gateway even though this gateway appears in the route list.
