Protocol Converters are devices that allow users or system integrators to convert a standard or proprietary communications protocol to a protocol more suitable to the application at hand and thus to achieve interoperability between systems. As an example, if you need to connect an IBM mainframe to a DEC mainframe you will need to use a Protocol convert of some sort.
Interface converters are devices that allow users or system integrators to connect equipment with a physical interface to connect to equipment that uses a different type of physical interface. As an example, you will need to use an Interface converter if you have an RS-232 cable that needs to connect to a V.35 interface.
BetterBox offers a full range of Interface and Protocol converters for most applications, G.703, Fibre Optic, Coax, Twisted Pair, etc.