Considering a computer network? What to expect is you decide to take the plunge.

As computers proliferate in a professional office, the time comes when their numbers can create a problem. Many people think it's when the office has a few as 3 computers. Others think problems don't arise until installations grow to 10 or 20. In reality, it's not the number of computers that determines whether an office can benefit from a network; it's how the computers are used. And even more important, how data is used by each computer.

Trouble first occurs when users begin carrying floppy disks from one computer to another to share data files with others in the office. If an organization's offices are not in the same building or the same city, the problem becomes more complited. In some cases, floppy disks must be sent by messenger or overnight express mail.

Software incompatibilities usually develop when users work with two or more different programs for tasks such as word processing, database management, electronic spreadsheets or business graphics. When that happens, they can't move data easily from one program's files to another's. The result is massive bottlenecks in the work flow.

It is equaly frustrating when two employees change different copies of the same file. At some point, the different changes have to be sorted out and merged. This is hard enough with two users. Imagine how complex the sorting and merging become when many users are changing different copies of an original.

All these problems--and more--are solvable with networks, which is why they are becoming so popular. A network lets computers share files, disk space and printers as though distinctions between the computers didn't exist.

ADVANTAGES OF NETWORKS

Networks enhance office productivity by making data sharing easier and by eliminating most duplicate files. They also create the following office efficiencies:

* Automated appointment and meeting scheduling. Networks allow users to share sophisticated scheduling functions. When someone proposes a meeting, the computer can automatically compare the unscheduled free time of those invited and then identify and display the unscheduled times they all have in common.

* Electronic mail. With e-mail, messages can be sent to one or several colleagues in a single step. It also facilitates very quick replies, message forwarding and incorporation of the text of a message into other computerized documents.

* Electronic meetings. A network also can function as a meeting environment, allowing each attender to participate without leaving the office.

* Cheaper software updates and maintenance. Without a network, computers are self-contained units requiring individual software installation, updates and maintenance. But with networks, one version of a software package serves dozens, or hundreds, of users. Considering how many software packages most offices use, the savings, in dollars and time, are considerable.

* Software standardization. Once the office has a network, central choices can be made about software for all users. In addition to allowing users to share data, this means everyone will be using the same type software; it now will be easier to train users (they can help each other and share tips).

* Safer back-ups data. Without a network, users take responsibility for backing up their own data, with somewhat spotty results. But with data stored on a network, a single person can back up everyone's data at once. This saves time and ensures secure data back-up.

A warning. As efficient as networks are, problems do exist. Network technology is complicated. Most people know one or more horror stories about network installation foul-ups. But such occurrences are becoming less frequent, and in general the technology has developed to the point where most network installations are relatively trouble-free.

HOW TO SET UP A NETWORK

Here is what a first-time network buyer should know. Complete off-the-shelf systems are available from knowledgeable, full-service retail stores. Their employees also can install and maintain the equipment. This is a viable approach for small, simple local area networks (LANs) that are confined to a single floor of a building or to several close-by buildings. But those interested in networking among widely scattered offices need more sophisticated gear. For them, it's wiser to turn to a more specialized networking consultant to custom design a system.

Finding the right consultant. Consultants proliferate as the need for special services grows. Many accounting firms and management consultants have added the speciality to their service menus.

These network consultants function much like value-added resellers in other areas of computing: They take a collection of off-the-shelf hardware and software products, add their own custom features and provide a client with a complete and customized turnkey system.

Network consultants are listed in the yellow pages or can be found through major vendors like Novell or IBM or through personal business contacts. However they are found, their experience should be evaluated carefully. There are many inexperienced and unqualified people who could create serious and expensive problems when they set up a new system. One good way to zero in on a competent consultant is to talk with decision makers in other firms in the area.

It also is good to be aware that some network consultants are more interested in selling a certain syste than in meeting a buyer's business needs. When such consultants are asked for evaluations, they'll nearly always finda network is needed. What's more, they'll probably find a need for the components they're most interested in selling.

To protect against this approach, compare several proposals from several different consultants. If there are wide discrepancies in the proposed networks, be sure the reasons behind them are clear.

WHAT A CONSULTANT WILL DO

A professional network consultant will perform three tasks: Analyze the flow of computer traffic in your office, consider the hardware and software options for a new network and make a formal recommendation and proposal.

The design of the network depends on how much data must flow among computers. To determine that, the consultant looks at office procedures and organization and determines the exact number, type and locations of computers to be connected. In many firms, this is just a matter of walking through the office and inventorying the installations. But in others, in order to make the most efficient use of the network, the consultant will have the figure on adding computers, printers, scanners, storage devices and other peripherals.

Once the consultant lays out the basic design, the next step is calculating the typical size of files people will be sending and receiving at each point on the network and how often they will be sending them.

In addition, the consultants will evaluate the special needs of various work groups. Will they need to communicate graphics, voice or video data? Do certain people or jobs require a special interface or special devices, such as scanners, printers or modems? Other area to be examined include

* The need for special application software.

* Requirements for data security and restricted access to important files, for data back-up, for personnel training and for hardware and software maintenance.

In addition, the consultant will try to determine a firm's technical expertise and ease in working with different levels of sophistication. That will help him or her decide what kind of network management a system will need.

Some firms have other specialized requirements, too. For example, a firm may not be able to afford to have its network out of service for even a minute. That would require the installation of more expensive "fault-tolerant" components. Instead of a component failure shutting down a network, in most cases it merely lights a warning signal on the network manager's control panel, while the network automatically compensates and continues to operate.

Once the evaluation and theoretical work are complete, the consultant will recommend network design, complete with hardware and software specifications. The final report will include a price for a network and a schedule for installation, training and completion of the project.

HOW CONSULTANTS CHARGE

Basically, consultants charge in two ways. Most want to sell a package of hardware, software and ongoing maintenance. They will not charge separately for the evaluation and system design. If a firm buys their recommendations, they will sell it all the equipment and install it. And, for an additional annual fee, they also will provide regular maintenance. Obviously, they run a risk. Unless equipment is ordered, they aren't compensated. And it's equally obvious their equipment prices are adjusted to compensate for that risk.

Naturally, the real cost for this kind of service depends on how much hardware and software are bought. Assuming a firm doesn't need to supply any users with new equipment, a safe ballpark figure for a network installation would be between $500 and $2,000 per user. The more frills and power that are added to the network, the higher the unit cost.

In some cases, a consultant will evaluate and itemize a firm's network requirements for a flat fee, which might fall between $1,000 and $2,000 for an average size firm. A client would be wiser to separate the evaluation from the sale of equipment. In that way it is more likely to get an unbiased recommendation from the consultant.

NETWORK OPTIONS

To a user, networking may appear fairly simple. But it's difficult to connect a number of computers and get them to communicate, share resources and function together (the industry word is "inteoperate"). Although some choices are highly technical and only the experts are qualified to choose among the options, there are these strategic considerations all buyers should be aware of.

* Hardware. If a firm uses only a single brand computer, the choices are relatively simple. But it's almost impossible to find a company using only one brand or even one type of computer. Therefore, it usually is necessary to select a network capable of connecting a wide range of computer brands, sizes, internal designs and operating systems.

In many situations, the power and data storage capacity needed to operate and manage the network would put a major drain on existing computers. Thus it may be necessary to add special computers to act as network servers. Selecting the exact size, type, operating system and storage capacity of these network servers is a strategic decision that balances cost against present performance and future growth potential for the network.

* Wiring. Today, most networks can function very well over standard telephone wires. Many newer office buildings already contain extra telephone wires for this purpose. But many firms choose to install special network wires in every office. This avoids the cost of expensive "concentrators" needed for networking over telephone wires. But costs can run up, because every time there's a shuffling of offices, new network wires have to be installed.

If a firm decides to install wires, it must choose the kind. The decision often is tied in with the choice of network operating systems, which in turn dictates network capabilities, speed and size.

In addition to telephone wires, many networks can transmit over standard coaxial cable. The choice will depend on the immediate requirements of the network being installed, as well as perceptions about the need for future expansion and upgrades of the network.

* Software. As always, IBM is the safe choice of operating system software for many business networks. But other network vendors, including Novell, 3COM, Ungerman Bass and Banyan, now offer network software with superb performance and enviable cost-effectiveness. Novell, in fact, has become almost the standard choice for many smaller networks that link personal computers.

Complicating the choice of network software is the opportunity to choose a computer operating system that contains built-in networking. Unlike the standard PC DOS so common in offices, operating systems such asUNIX and OS/2 don't require special networking software--that is, any application running on these operating systems can communicate with other computers over a network. UNIX, in fact, provides communications between a wider variety of computers than any other networking technology.

Macintosh computers are a separate issue. They can communicate with each other fairly well and, through special hardware and software, can be linked to computers running other operating systems, mainly DOS and OS/2. But choices are limited.

Similarly, there are options for tying personal computers into a network of minicomputers and a mainframe. In all cases, the hardware and software requirements--and limitations--are tremendously complex. A consultant will be needed to link each type of computer.

The network management functions are one of the most tedious aspects of operating a network. These include adding and subtracting hardware, software and users; monitoring and fine-tuning network performance; identifying and compensating for malfunctions; and reporting on network usage and costs. Some of this can be done manually using fairly simple network management software. However, manufacturers are steadily offering more powerful, but more expensive, network management software.

Clearly, the decision to get into networks is not a simple one. It involves a considerable investment of time and money, so don't act hastily.

ROBERT MOSKOWITZ is a business consultant based in Woodland Hills, California. He writes frequently on productivity, office automation and technology.