Hola Faustino,
De acuerdo a la guia las credenciales son las siguientes:
"Depending on whether you are a VAR or service provider, you might have different privileges. By default, the Administrator account name is admin, and the User account name is user. These account names cannot be changed.
If the service provider set an Administrator account password, you are prompted for it when you click Admin Login.
NOTE No default passwords are assigned to either the Administrator or User accounts.
Only the Administrator account can assign and change passwords.
The Administrator account can modify all web profile parameters, including web parameters available to the user login. The Administrator specifies the parameters that a User account can modify by using the Provisioning tab of the configuration utility."
http://www.cisco.com/en/US/docs/voice_ip_comm/csbpipp/ip_phones/administration/guide/spa500_admin.pdf
Espero que esto ayude.
Saludos,
Pablo
