HelixNet Main Stations accept linking as well as two-wire and four-wire optional interface modules, offering seamless connectivity to LAN and 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.Use our Digital Partyline Calculator to calculate the maximum acceptable cable length for a Clear-Com Digital Partyline System.