We will describe here how to set a Paging System with one Central Location and 7 Remote Locations spread over Internet, with public fix IP at Central Location only (e.g. the Remote Locations have 4G connections; devices are under NAT).

The hardware components are PS16 and Annuncicom 1000, all running STL firmware, configured in BRTP and with contacts gateway (to open the call on the amplifiers).

With BRTP is the player (Annuncicom 1000) that requests the stream and so "holes" the NAT.

On PS16 the stream (requested by the local players via BRTP) is always active and received by all the Annuncicom.
The upper row of keys on PS16 is mapped as contacts input (1 to 8 from left), configured to close the corresponding relays on all Annuncicom.
The relay triggers the amplifier: relay 1 on the location 1, relay 2 on location 2 and so on.
The relay 8 is connected in parallel on all the locations, used for "all zones" call.