Like many of the estimated 250,000 people displaced from their offices following the attack on the World Trade Center, Tom Cooper didn't stop working. Indeed, he and his colleagues at TradeCard, an import/export trade settlement firm, set up shop from their various homes.

Using email, the Internet, laptops, cell phones and conference call numbers, TradeCard employees located in the U.S., Hong Kong, Taiwan, London and Seoul remained in touch.

Now more than ever before, firms realize the importance of home offices for their employees. Such communication and computer equipment at employees' residences keep businesses running and save revenue during times of crisis. Home offices also increase the productivity of employees who need to juggle family and work responsibilities and, as a result, can't always be in the office during regular business hours.

"Companies will have to allow people to telecommute," says Neal Zimmerman, author of

At Work At Home

, which Taunton Press will release next month. "I don't think the words comfort and security are going to be freely associated with working in ultra-high rise office buildings anymore."

Additional attacks or bomb threats might force other workers in various parts of the country to work from home. During the week of the terrorist attacks, disaster recovery services provider

Comdisco

(CDO)

helped dozens of companies evacuate buildings in six U.S. cities besides New York and Washington, D.C., because of bomb threats.

"At the height of supporting people

during the disaster, we had 47 companies that declared 93 separate disasters," says Mary Moster, vice president of corporate communications at Comdisco.

Further, Moster believes company directors will disperse employees between different locations so that a possible tragedy wouldn't decimate business. "For disaster recovery's sake, it doesn't make sense to have all employees in the same office," she says.

What You Need

But not many people have the necessary equipment in their homes. So

TheStreet.com

thought it would be helpful to outline the basics for setting up shop.

The most essential and obvious tool, of course, is a telephone. But not just any phone will do. If you plan to use the phone a lot, it would be a good idea to get one with several lines and a display for caller ID -- a $100 to $300 investment, according to Karen Singh, manager of

Staples

(SPLS)

on 42nd Street in Manhattan.

A cordless phone with a headset would be even more useful for those who like to walk while talking or need their hands free to type. For workers sharing a home with pets or children, a mute button is almost essential, says Minda Zetlin, author of

Telecommuting for Dummies.

Next, if you plan to use the Internet, you'll need a second phone line -- or better yet, a cell phone, suggests Zimmerman. Cell phones, of course, offer mobility. Some even provide Internet access.

During the week following the attack, the large number of phone calls, emails and Internet usage crippled most land lines, and in many cases, cell phones provided the only way for many people in New York's Financial District to communicate, says Moster of Comdisco.

Also, don't forget your calling features, which aren't always helpful. Indeed, they can trip you up. Call waiting, for example, can interrupt a dial-up phone connection, Zimmerman notes. You also might want to change your telephone service plan. If you plan to make a lot of local calls, inquire about a blanket rate for unlimited usage.

Computing Power

Believe it or not, even now, not everyone has a computer at home. Telecommuting experts generally recommend a laptop rather than a PC because of mobility. Those who have made careers out of home office consulting, however, think PCs are more ergonomic and better for your back.

If you're not literate in computer specifications, here's what

TheStreet.com

recommends. Ask for a computer with a Pentium 800 processor speed with 128 megabytes of random access memory (RAM) and a 30-gigabyte hard drive, preloaded with Microsoft Office Suite. A V90 modem isn't necessary for those who have high-speed Internet access. Customers should pay no more than $1,500, but sufficient PCs can now be found for less than $1,000.

Internet Access

Most of today's laptops and PCs come with an internal modem for Internet access. You need to select a service, such as AOL, UUNET, AT&T or Sprint, to establish that connection. You also can hook up to the Internet through a cable provider, such as Time Warner. The Internet service provider (ISP) provides you with a phone number, user name and password. Here are two Web sites where you can shop for ISPs: http://www.comsearch.net/dsl.htm and http://www.dslreport.com.

Most areas in big cities provide high-speed Internet access, says John Wood, vice president of Derive Technology, an IT consultancy currently working with a number of firms formerly housed in the Twin Towers.

Finally, to work effectively, employees need to connect into their company's LAN, which is particularly important for data-intensive companies. If your computer lacks LAN connectivity, you still should be able to connect through a DSL or cable modem.