On the Older GL :
The OUT-OF-SERVICE RELAY is included in the GL-ACW,. Terminals 2 (common), 3 (normally open) and 1 (normally closed) are supplied as well, marked Service on the relay panel. If an error occurs that causes the GL-ACW to go out of service, the relay will be activated.
On the newer GL:
You would plug the auto dialer into the universal relay pan.