The Cisco Small Business SRP520-U Models is now obsolete (past End-of-Life and End-of-Support status).
End-of-Sale Date: 2013-08-05
End-of-Support Date: 2016-08-31
Cisco's End-of-Life Policy
You can view a listing of available Routers offerings that best meet your specific needs
If you want support information for the Cisco Small Business SRP520-U Models documentation, it may be available through Cisco.com Search or in the Cisco Community