I have a customer with 5 POTS lines and their system is currently setup in key mode - all 5 lines ring all extensions. They do not use a VMS, however I am installing Merlin Messaging 3.0, and they have requested that the AA handle all calls immediately. The question is, is there any reason to leave the system in key mode, or would it be wiser to switch to a Hybrid setup with the 5 lines pooled. This seems to make more sense to me since AA is handling calls. Any reason to stick with Key Mode, aside from customer familiarity and the fact they'll need to use SA appearances?