The Paging and Intercom module is used to set up an extension number that your users can dial in order to place an intercom call to multiple phones on your system at the same time.
For example, in a small office, you might set up a page group with extension number "100." When 100 is dialed by a local user, all of the phones in the office would go off-hook, and you could speak to everyone at every extension at the same time. Alternatively, you could set up page groups with different extension numbers for each department in the office, i.e. 100 for sales, 110 for service, and so on.
The Paging and Intercom module is related to the Extensions module. The Extensions module is used to create an extension. The Paging and Intercom module then allows you to select which extensions you want to include in your page group. You can also designate one of your page groups as the "Default Page Group." In the Extensions module, you can select whether to include the extension in the default page group.
See the User Guide