We order the HWIC-1DSU-T1= for Cisco 2900 series routers. I see that NIM-2MFT-T1/E1 works for voice and data on 4K routers. Which I think it is the replacement for VWIC3-2MFT-T1/E1 on 2900s, but I just cant find a replacement for the data only WIC or...