The Viking SA-X12 expander / adapter is an economical way to expand an existing paging system, while adding remote control to the new speakers. The SA-X12 can be connected to any existing paging audio source including 600 ohm line level, 4, 8, or 16 ohm speaker level, or even 25 volt and 70 volt paging systems. It can also be connected directly to the 2-wire protocol (40VDC + Audio) of another SA-X12 or the Viking SA-25 paging controller to add even more self amplified speakers. The SA-X12 takes audio from any paging or background music source, and combines it with 40 volts DC to run Viking self amplified speakers. The added Viking SA Series speakers will have the features of the existing paging system, plus have the added feature of being remote controllable. The SA-X12 can directly drive up to 12 Viking self amplified speakers which include the model SA-1S self amplifier ceiling speaker, and the SA-1H self amplified paging horn. Viking self amplified speakers have these advantages: 1) Audio and power are on the same pair (less copper). 2)Power is 40VDC for lower current and smaller gauge wire (less copper then older 4-wire 24 volt systems). 3) Non-Polarity sensitive for easier wiring. 4) Each speaker is infrared remote controllable so there is no need to install volume controls on the walls, or climb up ladders to adjust the volume. The SA-IR Infrared Remote and SA Series speakers are available separately.