def bytes_to_pascals(dg_bytes):
    """Takes a list of 3 bytes read from the DG-700 and returns a pressure
    in Pascals.
    Larry Palmiter originally wrote this code for TEC in Basic, 
    which has proven immensely useful.
    """
    bx, hi, lo = dg_bytes    # unpack the array into individual values
    pressure = 0.0
    if bx == 0:
        pressure = 0.0
    else:
        x = bx - 129
        if hi > 127:
            pressure = (-1.) * 2.**x * (1 + (256 * (hi - 128) + lo) / 2.**15)
        else:
            pressure = 2.**x * (1 + (256 * hi + lo) / 2.**15)
    return pressure