I am using Dialer Profiles(DDR-Dial on Demand Routing)  to set up a connection that never drops on 809 routers. The key word is "Dialer Persistent" in a Dialer1 interface. Even though it is "Dial on Demand" it is a connection that never drops.   for the cellular interface, set up  no ip address ip virtual-reassembly in dialer pool-member 1 dialer in-band   for the Dialer interface ip address negotiated ip virtual-reassembly in dialer pool 1 dialer string (stringname) dialer persistent    Dialer 1 is what I have been using.  I frequently get an error message to "remove legacy ddr configuration" and the fix for that is to go into config mode, in the cell 0 interface, "no dial in-band" , wait a minute, "dial in-band" and "dial pool-member 1" also in the config, is a default route (zero route) to the dialer1 interface, and a dialer-list1 protocol ip permit   Hope it helps ... View more

Greetings Jesus, I don't mean to question your research into the compatability of your T1 interface, but a 1900 series router running Cisco IOS 15 seems to be a little new to not support a v2 WIC.  Maybe it was a misprint.  Maybe the 1900 supports V2, but not V1.  I was told the 1800 routers needed a V2 WIC, which would make it seem odd that a 1900 would only support a V1.  Have you tried the V2 interface in your 1921 router? Would it be possible to share a show interface, with the ip address/subnet xxx.xxx'd out? Are there any hints in a "show controller" output? -djs ... View more