The 'C5x DSK is designed to directly connect to a microphone and an 8-ohm speaker via RCA jacks. The I/O RCA jacks are directly connected to the dual A/D and D/A converter called the Analog Interface Circuit (AIC). In some instances the microphone does not generate the signal level required for the AIC to detect and convert the signal. It is suggested that a dynamic or amplified (pre-amp) microph