This paper presents the system level study and optimization of the data-detection (datapath) for the body-coupled communications (BCC) receiver. The datapath is part of the analog-front end of the receiver and performs correlation-based coherent detection. The datapath consists of an LNA (band-pass filter), a correlator and a slicer. The blocks are modeled as linear systems and the calculations are done in MATHEMATICA. The focus in this work is the datapath's bit-error rate (BER) performance. In this paper, the BER robustness to interference (RFID and other) and to the synchronization errors is analyzed. The impact of the inter-symbol interference (ISI) on the BER is also calculated. It is shown that the datapath performs well in an AWGN channel. The role of the filter in achieving good BER performance is analyzed. A strong Gaussian man-made noise significantly deteriorates the BER. The correlator's correlation time and the band-pass filter's corner frequencies and roll-offs are optimized against this noise for achieving as low BER as possible.