The Cisco SR 520-T1 Secure Router is now obsolete (past End-of-Life and End-of-Support status).
End-of-Sale Date: 2012-01-27
End-of-Support Date: 2017-01-31
Cisco's End-of-Life Policy
You can view a listing of available null offerings that best meet your specific needs
If you want support information for the Cisco SR 520-T1 Secure Router documentation, it may be available through Cisco.com Search or in the Cisco Community