The CMX208 is an ISDN telephony protocol engine which implements the lower level ISDN interface and communicates with the CMX605 and other standard devices to form a fully integrated ISDN chipset for voice communications. The CMX208 puts all the main data processing elements in a single device. No ISDN software has to be written and simple `Plug and Play' design results. This reduces development time and provides a highly cost-effective hardware solution. By using proven circuit designs, the designer can move quickly from initial concept through design in to manufacture. The CMX208 supports two voice ports over the ISDN Line, which can be used to provide ISDN telephony services or POTS line interfaces, and has independent keypad-configuration of these services for each port. The CMX208's feature set and architecture allow most analog systems to be converted to an ISDN equivalent with enhanced features.