I'm not sure if Minicom is what you want to dial-up. It may serve you better to just write your own small dial-up script to make sure all the settings are correct and that it'll use pppd directly instead of a com prog. The NO CARRIER is probably due to your phone hanging up, because it either, can't authenticate you or the protocol is wrong etc...Here is a link to a nice little how-to if you'd like to try it this way:
[Go Here]