I found that i need to install an IOS upgrade to my router to use the HWIC-1FE module I purchased. I have a Cisco 2821 router. From the spec sheet i read that i need a minimum IOS of 12.4(15)T. I called my Cisco retailer and he send me the following file c2801-advsecurityk9-mz.124-22.T.bin . When i tried to load this it says it is not for my hardware. I am guessing this is because it begins with c2801 and i need it to be c2821? Should i ask for a different file? Could i just rename it? Thank you for your help!