The answer depends on the type of network outage. If the gateway is down, paging will not work. If a switch is down, the phones connected to that switch could not page. One solution would be to have an analog phone connected to an FXS port on the gateway. This would cut out all points of failure except the gateway. You could also possibly connect the analog phone directly to the paging system which would cut out all network related failures.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.