Emerging medical applications require device coordination, increasing the need to connect devices in an interoperable manner. However, many of the existing health devices in use were not originally developed for network connectivity and those devices with networking capabilities either use proprietary protocols or implementations of standard protocols that are unavailable to the end user. The first set of devices are unsuitable for device coordination applications and the second set are unsuitable for research in medical device interoperability. We propose the Medical Device Dongle (MDD), a low-cost, open-source platform that addresses both issues.