This paper starts with the background and causes for the reconstruction of the SDH access loop

and then thoroughly approaches the general process

time distribution

customer coverage

and principles for the annual routine reconstruction of the SDH access loop.Moreover

it emphasizes that attention must paid to the key step cutover in the reconstruction.This paper is a guide to preventing adverse effect of the access loop in the networking and cutover to the customers

saving investment

guaranteeing smooth network upgrade and network security

and improving network capacity and network bandwidth usage.