Computers can talk to each other and provide a conduit between people in the same office or on opposite sides of the world.

Computers can be linked directly in a work area, called a local area network (LAN). Special LAN software allows many computers to share software applications and peripherals such as disk drives and printers. Each computer on a network operates as a separate machine.

A modem allows you to transmit and receive information without a network. Transmitting a file is called uploading, and receiving one is downloading. (As with other peripherals, a modem is designed to operate on either an IBM-compatible or a Macintosh platform.)

A modem also opens access to the Internet. The Internet allows you to shop, read the news, trade stocks, make reservations, conduct research, chat and send e-mail.

To access the Internet you must subscribe to an Internet Service Provider. Many modems are bundled with a free trial subscription to America Online, the Microsoft Network or other ISPs.

Modem Features

A modem is either built into a computer or an external. In either case, you may find it helpful to have a second, dedicated phone line for modem and fax.

How fast a bit-by-bit data stream is sent is measured in baud, or bits per second (bps). The higher the speed (or baud rate), the faster data can be transmitted and received. Most newer computers come equipped with a 56 kbps modem - 56,000 bits per second. A 33.6-baud modem can receive files transmitted at slower speeds such as 14.4 kbps, but cannot receive files transmitted at 56 kbps.

A modem can transmit and receive faxes directly from your computer. Using this fax modem, you can write a letter on your computer and fax it to its destination without ever printing it.

You can receive faxes, which you display on your screen, print, save on disk for future reference or erase from your system.

Some modems incorporate telephone-answering devices that enable your computer to answer the phone, play an outgoing message and record the caller's message onto your hard drive. Such modems are handy, especially for multiple users. Using communications software, multiple mailboxes can allow callers to leave messages for specific family members or co-workers.

Other features include caller ID, fax forwarding, voice mail forwarding, call screening and virtually anything available through normal telephone answering devices.

Internet Access

In addition to phone lines, consumers are finding newer and faster way to access the Internet.

• ISDN (Integrated Services Digital Network) is a special telephone company technology that can provide up to 128 kbps. ISDN requires special modems and wiring, and not all local phone companies have the necessary equipment to provide this service.
• Cable modems can supply speeds double, triple even quadruple those of analog modems because they use the same coaxial cable used to deliver your cable television service. Although cable modems are capable of high speeds, the signal is shared among subscribers in a specific area. The more subscribers, the less bandwidth there is available to each individual user.
• DSL (Digital Subscriber Line) service from telephone companies can provide Internet access at up to 1.5 megabytes per second. DSL uses a greater range of frequencies over a wire than traditional telephone services. This allows for greater bandwidth with which to send and receive information. No special wiring is needed, but you will need a DSL modem.

Viruses

When you download a file, you may download code you hadn't intended. Sometimes this code can harm your computer. This harmful code is called a virus because it can infiltrate your circuitry, harm your machine, damage your software and programming and destroy your data. A virus can be programmed to wait until a certain date or time to invade your data, or until you perform a certain function or task.

The best way to protect your system is to invest in virus protection software, which can detect its presence and warn you. Companies that make this software send out periodic updates of software to detect the newest strains.

Other precautions:

• Don't accept e-mail or attachments from unknown senders.
• Do not put shareware (free or low-cost software available on the Internet) on a hard disk where you have data stored. Download it onto a floppy or removable hard disk. For further protection, deal with a shareware company that collects and tests shareware, then offers it for a nominal fee. User groups and publications for computer users can help you find a shareware company.

There probably is no way to be completely safe from viruses.