The EV8500 Evaluation Kit comprises a single board containing a CMX850 Communications Controller (80C51 core and V.22 bis Modem IC), line interface components and a serial communications port for interfacing to a PC. Firmware is provided to implement a standard `AT' commands interface which is used to control the evaluation board via a standard terminal emulator. PC software is provided to support serial downloading of firmware updates to the evaluation kit. The board is powered from a single 3 3.6V dc power supply. Removal of jumpers allows the user to measure device current. Important signals can be monitored via test points and header pins. The evaluation board has a 2-wire line interface to provide line matching and dc isolation. This 2-wire interface is connected to the line using an OptoMOS relay. Where components are telco-specific (line impedance, line protection, etc.) space is provided for the user to add appropriate components.