Dial up is a means of connecting to the Internet using a modem. Dial up modems use the phone line to establish a connection to an Internet Service Provider (ISP), and then on to the Internet. The modem alters the digital data from the PC to an analogue signal that is compatible with a phone line and then does the opposite with the information received, changing it into digital information. What is a modem? Modem stands for Modulator/Demodulator. The name derives from the technology used in modems, which takes a digital signal and either converts it to an analogue signal (Modulates it) or converts an analogue signal back into a digital signal (Demodulates it). ISPs Internet service providers. The companies who provide you with access to the internet via a dial up phone number. Dial up is the original method of connecting to the [+]