Hi the DC input current of 2821 is 12A (24V), 5A(60V) startup current 50A<10ms. Power dissipation of DC is 300W (1024 BTU/hr). RPS recommended is RPS-675.Hope it helps.Thanks
if you do not know the interface number and you dont have the priv for show runn command for viewing the running config, still you can use show interface and you would be able to see all the interfaces in the Router.Thanks