[tsaksa]

It looks like most of the common causes for this problem have been described very well, but I thought I would add one more possibility for anyone searching this thread. Our team had no connectivity to the accelerometer at first with any cable combination. It turned out that the accelerometer was responding to the alternative address even though no jumper had been added to the board. I tested the jumper with an ohm meter and did not find a short, but the device clearly acted as if it had been programmed with a jumper. If anyone else has trouble with no communications at all over I2C, try both addresses before giving up, even if there is no solder jumper on the board.