To optimize availability in the Telecommunication (MTTR) it requires to design the number of the energy power units (redundancy degree) through its failure-probability (MTBF) and time-maintainability (MRT)

The power supply to permit telecommunication devices to work and obtain maximum energy availability being furnished to the corresponding prerequisites, but consensually to the author, to consider the importance of this fact, determined a new course in developing the projects in telecommunication involved in the major part the world has analyzed the singular effect of requirements. To optimize availability in the telecommunication (MTTR) it requires to design the number of the energy power units (redundancy degree) through the its failure-probability (MTBF) and time-maintainability (MTBF). Therefore the author has developed a theory to scientifically acknowledge the statistic law that relates the risk-benefit to the maintenance, observing the chain to singular elements of itself. The analysis starts from the word "safety" and the word "security" specifying the meaning in our technologic world, subsequently to arrive at the parallel and serial structures that are responsible for desired telecommunication availability.