Can anyone help me to setup paging or like a public announcement system for the IP phones on CCM 4.1(3).
Do you have an existing overhead analog paging system? If, so then you'll need an FXO port to integrate it with CCM. If you want to use phones for this soltion CCM does not have paging solution out of the box, the only thing you can so is setup the DN for auto answer and all incoming calls will be automatically answered via speakerphone.
There are third party paging solotions for CCM such as Berbee Informacast, if you are interested.