Types of dial up services include V.34 and V.90 modem as well as Integrated Services Digital Network (ISDN). Dial up systems utilize special-purpose network protocols like Point-to-Point Protocol (PPP).
To use a dial up Internet connection, a client modem calls another modem located at the Internet Service Provider (ISP). The modems transfer network information over the telephone until one modem or the other disconnects.
When the popularity of the Internet exploded in the 1990s, dial up was the most common form of Internet access due mainly to its low cost to setup. However, the performance of dial up networking is relatively poor due to the limitations of traditional modem technology. V.90 modem dial up supports less than 56 Kbps bandwidth and ISDN handles approximately 128Kbps.
Many home users are currently replacing their dial up services with high-speed broadband technologies that operate at much higher speeds.