With the evolution of telecommunication network from TDM to packet based network and the development of mobile communication technology

legacy digital synchronization network supported mainly by frequency synchronization is being replaced by the next generation of time & frequency synchronization network with the support of frequency/phase/time.So the function of stand-alone T&F synch node supply will also be changed.This paper presents a new type of function model of stand-alone T&F synch node supply

and the rules and procedure of selection of system reference resources based on this new function model is also discussed.