The purpose of this document is to outline the prototype implementation for the Mountain Rescue service trial. It provides an overall picture of which components have been implemented, how they work together and the methodology of the trial. It is the conclusion of 18 months of discussions, analyses, development and lab/field trials. All the results from the Mountain Rescue trial are reported and analysed in the companion deliverable, D4.2.3 Report on the Mountain Rescue Service Trial.