The EV8000 Evaluation Kit comprises two boards. The signalling processor board contains an FX828 and an FX829. An FX818 is also provided and can be fitted in place of the FX828. The signalling processor board is powered from a single 8 - 35V dc power supply; an on-board regulator sets 3.3V or 5.0V operation. LEDs indicate the status of the FX829 carrier detect output and the FX828 comparator output. Both of these lines are available on the same connectors as the C-BUS. The FX828/818 and FX829 may be driven from a common external clock, or from a common crystal oscillator. The supply current of either target device may be measured by removing the appropriate jumper. A user prototyping area is provided and important signals can be monitored by test points. There is an on-board microphone and a loudspeaker output. C-BUS signals can be applied at either of two connectors (J1 or J2). The other can be used to add future C-BUS evaluation kits in parallel with the EV8000. A third connector (J3) provides a daisy chained C-BUS to enable a second EV8000 signalling processor board to be controlled from the same PC. The signalling processor board can also be used with a user's own C board, with appropriate software. Component footprints are provided in case the user requires level shifting between the CBUS input logic HI and the VDD level of the signalling processor board. The C board is fitted with a PIC C containing the firmware to interface a PC serial port to the TM