To connect to an overhead paging system, you must first determine the type of interface involved. Overhead Paging systems can have any of three different interfaces:FXS (station port like on a SPA122)FXO (CO line interface like the second port of a SPA3102).RCA or paging port (line level audio)For systems with an FXS or FXO interface, a standard SIP ATA adapter will work fine. The Linksys SPA3102 is commonly used to connect to these types of FXO facing systems.Note:  It is not possible to connect a Polycom or Yealink multicast page group to a standard SIP ATA that does not support multicast paging. To page an overhead system connected via an ATA, the Polycom or Yealink phone must make a point-to-point (extension to extension) SIP call to the ATA.For systems with a RCA (line level) interface, you will need a SIP capable paging alerter such as the Cyberdata SIP Paging Adapter (Part # 011233). The Cyberdata product will register as a SIP extension, and is able to emulate Polycom multicast paging so that it is possible to page from a Polycom phone to the overhead paging system. The following diagram shows the interaction between a Polycom phone with multicast paging, the SkySwitch hosted PBX, and an overhead paging system connected to a Cyberdata unit.Manufacturer Notes* AlgoPlease refer to manufacturer website* Bogen TPU SeriesRequires a TAMB2PS or UTI1, connects to an FXS port.  * Bogen TAMB2Connects to FXS out of the box - just set DIP switch 1 to ON, 6 to off for CPC disconnect. Connect FXS gateway to the Station/Trunk jacks.* SPA3102 NotesNOTE you may have to adjust the line-in voltage on the SPA3102.Set PSTN Line>Dial Plan 1 to blank* Snom SNO-PA1Snom has developed a SIP bridge (PA1) enabling businesses to extend their existing public announcement speaker system while upgrading from digital/POTs systems into SIP-based voice communication solutions.  * Valcom V-2001a/V-2003a/V-2006aIdeally use a Linksys SPA3102's FXO port to connect to the RJ11 jack.If using FXS: Order Valcom V-9970 & VP-412A (power) to adapt to FXS interface. Connection diagrams are attached.http://www.valcom.com/techsupport/pagecontrol_ts/v-9970.htm* Viking PA-2AIdeally use a Linksys SPA3102's FXO port to connect to pins 5 & 6, turn Talk Battery OFF.Note: Contact Viking support for firmware that supports Outbound Proxy authentication.If using FXS: Add RAD-1A use 600ohm out to PA-2A ports 5/6. Plug FXS into phone line in on RAD-1A.