In the list of network components to add, select Protocol and then click the Add but-

Appendixes Identifying analog modems Analog modems come in 28.8, 33.6, and 56 Kbps, but most likely, your modem is a 56 Kbps modem. Although you can use any of these for remote access, the slower the modem is, the slower your connection to the remote computer. If you’re planning to access a small file and then disconnect, slower modems might work fine. If you want to work for very long on a remote computer, however, you’ll that find the faster modems are best. Most newer modems use data compression, so the throughput can be faster. Modems that run at 56 Kbps are very affordable and offer fast downloading and uploading speeds. All data communications devices upload and download at different speeds. Down- loading speeds are always faster. More people download than upload, so most servers, lines, modems, and other technologies make sure that downloading speeds are fast. For a 56 Kbps modem, download speeds range as high as 53 Kbps and uploading speeds are usually around 33 Kbps. The actual speeds depend on the telephone lines and the connection. The FCC’s regulations prevent us from using 56 Kbps in the United States, so you won’t see any speeds above 53 Kbps or so. Recognizing digital modems Digital modems are becoming more common in small businesses and corporate offices because they’re not as expensive as they have been in the past. One of the problems with dig- ital lines is the fact they’re not available in many rural areas. Prices and availability vary greatly from area to area. You might expect to pay a 100 for the modem, around 30 to 60 a month for the line, and perhaps 2 to 5 cents a minute for connection time. If, however, you work at home a lot, your company may want to install a digital line for you to use. If you have a digital line, you can work via a VPN to connect to your company. Integrated Services Digital Network ISDN is a digital modem and data transmission line that supplies voice, video, audio, and data transmissions at high speeds. ISDN offers low noise and interference, security, and consistent service. Again, ISDN is not used as much as it once was. The ISDN modem is actually a terminal adapter TA, but using the term modem is common and accepted. One TA is located on your end of the ISDN line, and another TA is located on the other end at the phone company. With ISDN, your data should transfer with speeds of up to 128 Kbps with uncompressed data. Generally, an ISDN line can be no longer than 18,000 feet, although you can install special equipment to extend the distance. Note Understanding V Standards V standards are a way of rating modems and other data communications. These standards apply to facsimile transmissions, modems, and local area networks. Manufacturers meet these stan- dards to make their products compatible with other manufacturers’ products. The V.90 standard for a 56 Kbps modem is mature and stable. Often, when a standard needs an upgrade or has problems, a manufacturer upgrades the firmware in order to make the changes. Firmware is any software stored in the form of read-only memory ROM and is part of the modem’s design. When a standard is well established, like V.90, manufacturers don’t have to upgrade it very often. 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.