HelixNet main station accepts both two-wire and four-wire optional interface modules, offers seamless connectivity to virtually all common two-wire and four-wire audio systems. The HLI-4W2 interface module provides an easy way to interface common four-wire audio paths such as matrix ports, cameras and telephone circuits with a HelixNet main station. Each of the two ports employ both transformer and electrical balancing to ensure incoming and outgoing audio paths are free of hum and noise.