Ativa router and at&t

there is a link in the motorola UI that allows it to be put in "bridged mode" so you can configure the router. however, before you do this, i suggest you have to make the motorola (is it 2100?) modem work with your computer, connect this modem to your computer using ethernet connection, access the UI (192.168.1.254), type your user id & password in the login page, then connect. make sure that you are able to connect to the internet. then access the UI again, click on "advanced" choose PPP location. in the PPP location page, click on bridged mode, that will restart the modem automatically, & you will notice the modem's internet light will turn off. then you can connect the ativa router to this modem using manufacturer's instructions. you can now login to the router's page and make the necessary changes.