When it comes to the Merlin Messaging voicemail system, the ports that the voicemail system is connected to need to be in a
Calling Group and set up as
Integrated VMI and
Linear Hunt.
In Key Mode, if you want the voicemail to answer immediately you would assign lines to the voicemail's Calling Group. If you want a delayed answer (to give a someone a chance to answer incoming calls for instance), you would assign telephone lines to another Calling Group and have them overflow to the voicemail's Calling Group and also build a mailbox in the Merlin Messaging with a "
Class of Service" of 15.