Dial up connection requires a username/password & a modem to connect to internet.The maximum speed will be of 56kbps only. In this either the phone or the internet will work at a time.

While in broadband connection (it need a modem & may need user/password).It is directly connected with RJ45 LAN card. Its speed ranges from 256kbps to several mbps. In this both phone line and internet can work together.