NerdNet linked repeater design

The design goal for NerdNet was to connect treasure coast repeater to a common hub for sharing of resources.
The ability for any "member" repeater to join the link on demand requires a simple TouchTone command from the user. The commands should be a simple and intuitive.

The HUB is responsible for setting up and tearing down a link with as little human intervention as possible.
All member status is tracked by the HUB in real time. Member repeaters request a link to another member or shared HUB services. HUB services include IRLP, Emergency Autopatch, HF remote base and Satellite/Internet delivered ham related programming.

A link request from a user on a member repeater is queued in the member controller. The member controller checks for hub activity before sending the DTMF command to the HUB. No audio connection is yet made from the member to the HUB. The HUB maintains a table of all member repeater status. If the requested member is already connected to the HUB, the HUB simply responds back to the requesting member with a link established.
The requesting member sets up the audio connection and reports to the user.

To make this possible member repeaters require a controller capable of the following features.
     Duplex Link/Remote base port.
     Ability to accept DTMF from the Link port.
     Ability to generate DTMF to the Link port.
     Spoken messages to the user.
     Macro commands to simplify user/hub commands.
     Scheduler for automation. 
    Command execution based on external events.

Member repeater status can be any of the following:
     Not connected.
     Connected to the HUB.
     System Down.
     Do Not Disturb.

HUB status can be any of the following:
     Connected to IRLP.
     Connected to HF remote base.
     Connected to Autopatch.
     Connected to Satellite receiver.
     Connected to Internet audio stream.