Some embodiments of a portable medical device, such as an infusion pump, can receive an external reference signal (e.g., a radio, cellular and/or satellite signal) to provide an automatic time-setting and maintenance operation. In these circumstances, the medical device can maintain accurate time and date information even in the event of a power interruption, a time-zone change and/or an internal clock error, for example. In this manner, the portable medical device provides safe operation and added convenience to the user.