Dial-up internet access, usually just called Dial-up, is a slow way of connecting to the Internet by using a telephone line. A modem is connected between a computer and a telephone line and then the modem is instructed to dial the phone number of an Internet service provider (ISP) to connect to the Internet. The ISP must be a dial-up service provider with several dial-up modems waiting to accept dial-up calls. This kind of internet is slower than DSL. 