Sigtronics SPA-400N Intercom

The Intercom That Set The Standard Sigtronics pioneered the voice activated intercom market in 1974 and continues to deliver value and performance today in the 4 or 6 place FAA TSO approved SPA-400 / 600 intercom series. With fail safe features that allow pilots to always hear the radio even if the intercom is off, and radio priority that assures ATC only hears the crew member transmitting, the SPA intercom series is the standard by which all others are judged. Individual Mic Bias Allows The Use of Different Brands of Headsets General aviation headset microphones draw power from the intercom or radio mic line. Some poorly designed intercom systems hook all the headsets to one mic line so that all the headsets must share the same power. Because different headsets have different power requirements, one headset may draw just enough power to work but there may not be enough power left over for any of the other headsets to function. Wi