Select the TCPIP protocol that is bound to your network card as opposed to the

Appendix C ✦ Telecommuting Digital Subscriber Lines DSL are more expensive but much faster than ISDN lines. You con- nect two DSL modems to transmit the data at 160 Kbps. There are several types of DSL some- times represented as xDSL. Asymmetric DSL ADSL is the most commonly used xDSL line. ADSL transmits at speeds of up to 6 Mbps and is therefore somewhat expensive. Cable modems are another broadband device that you can use in your home or small business. Cable modems quickly transfer data and are targeted more to homeowners than business owners. Looking at communications lines Each type of modem or other data communications equipment has specific line types it can use. Analog modems, for example, communicate over plain old telephone POT wiring. The speed of the communications depends on the line. Generally, digital lines are leased from a phone or other telecommunications company, and they are nearly always dedicated lines. A company, for example, might install a digital line between two branch offices for faster communications than with a modem. The line is always there, ready to use when someone wants to connect. ISDN provides two types of lines: Basic Rate Interface BRI and Primary Rate Interface PRI. BRI is not quite as expensive as PRI and provides 128 Kbps speeds. PRI provides speeds of 1.536 Mbps, so it is considerably faster. Because of the expense, mainly larger corporations and government agencies use PRI. Cable modems use the same coax cabling used for TVs. The cable company installs the cabling for you. DSL uses existing phone lines. Frame relay, T1, Fractional T1, and T3 are other communications lines that are high in quality and quite expensive. The following briefly describes these technologies: ✦ Frame relay supports speeds of 56 Kbps, transmits voice and data, and has no distance limits. Frame relay’s equipment, however, is expensive, and the voice transmission quality isn’t the best. ✦ T1 is a high-quality communications line. Total speed is 1.544 Mbps, and a T1 line is reliable. Because of the expense, T1 is best for corporations connecting a large number of users. ✦ Fractional T1 is a part of a T1 line. The speed is less than that of a T1 line but better than ISDN and frame relay. Also, as your network builds, you can add Fractional T1 lines to increase speeds. ✦ T3 is a long-distance communications line that reaches speeds of over 44 Mbps. T3 is very expensive and is used almost exclusively by ATT and the regional telephone operating companies. Installing and Configuring a Modem If you don’t have a modem installed in your computer, you must install it before you can remotely access another network. You also can use a modem to connect to the Internet or another communications service, such as America Online. Most newer computers come with an interior modem already installed; however, if you must install a modem, purchase an exterior modem.