The Viking model PSA-TB-IP Paging Speaker Adapter with Talk-Back enables you to quickly convert any 8 ohm, 25V or 70V analog paging speaker into a SIP endpoint paging speaker. The microphone enables Talk-Back and also monitors room noise to automatically increase the speaker volume when necessary. After the quick conversion the speaker can then be used for standard one-way SIP endpoint paging, two-way conversations via SIP endpoint paging, one-way multicast paging and making standard or emergency two-way SIP calls initiated from its switch input.