Dial Up uses telephone lines to connect the PC to the internet. The modem in the PC calls the Internet Service Provider to gain access to the internet.
Broadband connection also uses telephone lines but the ones which are not used for voice transmission. So the connection doesn’t get affected due to voice transmission.
Each time to modem connects to the ISP , the PC is assigned the unique IP address so that it can be uniquely identified.
The transmission speed can go upto 50 mbps which is way higher when compared to dial up connection.