Dial *96 and then the zone number.
Through the PBX.
Select the paging button or soft key on the phone.
Dial * and then the zone extension.
For Polycom's, you can choose from a list of zones and for Ciscos you dial *96 and then the zone number.
You have to switch between different profiles to transmit to different zones.
You can't, you will transmit to any zones that you have permission for.
You dial * and then the zone number.