ATTENTION PLEASE:
What's the difference
between intercom and paging?

An intercom call is two-way (a conversation), from one phone to one phone.
Paging is one-way (an announcement), from one phone to many phones, or speakers.
Stupidly, some AT&T phones have a "paging" button that makes a one-way announcement to one phone.Also stupidly, the "paging" feature on Panasonic's KX-TG2000 and 4000 systems just makes all the phones ring at once -- pretty darn useless.
We're probably a few years away from being able to make paging announcements to multiple cordless phones in a phone "system," but the feature is available in multi-handset cordless phone packages.