One embodiment of the present invention relates to a communications system. The system includes a Highway-Addressable Remote Transducer (HART) transmitter comprising a direct memory access (DMA) module configured to access at least one transmitter lookup table (LUT) using DMA transfers to modulate a HART data packet into a frequency-shift keying (FSK) data signal. The system also includes a HART receiver configured to demodulate a received FSK data signal into a demodulated HART data packet.