Replaces Cisco ADSL & 1841 router as this is a Fast Ethernet only router, the 1921 is a similar router but with Ge0/0 and Ge0/1 interfaces and two hwic slots. I have a EHWIC-1GE-SFP-CU card as well because in the foreseeable future I will need to bring the internet in from the ISP ONT. Note this is NOT a direct fibre from the ISP, it is fibre to the ONT, then a Ethernet to fibre converter and on to the 1941 SFP fibre in a different building.

First problem…

Router#sh diag
Slot 0:
        WIC Slot 0:
        Unknown WAN daughter card
        WIC module not supported/disabled in this slot
        PCB Serial Number        : FOC15164VRP
        Hardware Revision        : 1.0
   ... edited ...    
        Product (FRU) Number     : EHWIC-1GE-SFP-CU

I'm running

Cisco IOS Software, C1900 Software (C1900-UNIVERSALK9-M), Version 15.0(1)M4, RELEASE SOFTWARE (fc1)

And the Cisco Support page for the EHWIC says the 1921 requires Cisco 1921 ISR - Release 15.1(4)M

So I need to find this IOS release first.