Now that IP networks are becoming the de-facto standard the world over, it is easy to forget that there are thousands of old legacy networks and connections still out there that need supporting. This is where copper to copper products come into play.
Many companies and Government departments, including the MoD, still rely heavily on this proven, legacy technology. Third World and underdeveloped countries also use older technologies to provide their main communications infrastructure as they can't afford costly upgrades. Copper to copper products enable such companies and countries to make the most of an existing infrastructure.
For example, if a company has a legacy piece of communications equipment with an X.21 or V.35 interface, and the only network connectivity available to them is a 2Mb G.703 link, a copper to copper (X.21 to G.703) converter could be deployed to enable lower speed connectivity over IP networks or even SDH networks. The example below shows traditional voice connectivity over an IP network, which makes the most of an existing investment in legacy infrastructure.