You can connect a DID trunk to Branch Gateway using one of the compatible ports.

The trunk analog telephone port on the Branch Gateway front panel forms a mechanical analog relay with the LINE port next to it. You can configure this relay to provide emergency transferred telephone service in the case of a power outage or disconnection from an external server. During an emergency situation, all incoming calls on the trunk are directed to the phone plugged into the LINE port. The phone also uses the trunk for outgoing calls.