Summary

50 IT Essentials: PC Harware and Software Companion GuideIn the 1990s, the Internet typically was used for data transfer. Transmission speeds wereslow compared to the high-speed connections that are available today. Most Internet connectionswere analog modems that used the plain old telephone system (POTS) to send andreceive data. In recent years, many businesses and home users have switched to high-speedInternet connections. The additional bandwidth allows for transmission of voice and videoas well as data.You should understand how users connect to the Internet and the advantages and disadvantagesof different connection types.After completing this section, you will meet these objectives:■■■■Describe telephone technologies.Define power line communication.Define broadband.Define VOIP.Describe Telephone TechnologiesSeveral WAN solutions are available for connecting between sites or to the Internet. WANconnection services provide different speeds and levels of service. Before committing toany type of Internet connection, research all the available services to determine the bestsolution to meet the customer’s needs.Analog TelephoneAnalog telephone technology uses standard voice telephone lines. This type of service usesa modem to place a telephone call to another modem at a remote site, such as an Internetservice provider (ISP). Using the phone line with an analog modem has two major disadvantages.The first is that the telephone line cannot be used for voice calls while the modemis in use. The second is the limited bandwidth provided by analog phone service. The maximumbandwidth using an analog modem is 56 Kbps, but in reality, it usually is much lowerthan that. An analog modem is not a good solution for the demands of busy networks.Integrated Services Digital Network (ISDN)The next advancement in WAN service is ISDN. ISDN is a standard for sending voice,video, and data over normal telephone wires. ISDN technology uses the telephone wires asan analog telephone service. However, ISDN uses digital technology to carry the data.Because it uses digital technology, ISDN provides higher-quality voice and higher-speeddata transfer than traditional analog telephone service.ISDN digital connections offer three services: Basic Rate Interface (BRI), Primary RateInterface (PRI), and Broadband ISDN (BISDN). ISDN uses two different types of