Best migration from callmanager 4.2

I’m working on migrating away from callmanger 4.2
I can get asterisk working and placing outbound calls using the cisco call manager as a sip trunk and then the callmanager passes the call to my voice gateway (1760V router).
But when I’m ready to pull the plug on call manager how do I get asterisk talking to my PRI line using the cisco 1760 router that has FXO cards in it?
Do I really need to buy some digium card or what is the way to do this?


I’m not a prof on cisco’s, and i apologize if my post is off-topic, but i know that we had one in past. If it can support SIP, you can just set it to send calls to your asterisk (and configure entry point in your sip.conf) or dial out using Dial(SIP/5551234567@