Wireless Hardware Connections

A new and easier way to link IBM-compatible computers, printers and modems has been introduced by a company that uses low-power radio frequencies instead of cable or wire to make the connection.

What the LAWN (for local area wireless network) from O’Neill Communications Inc. of Princeton, N.J., achieves in simplicity and flexibility, however, it gives up in transmission speed.

Making trade-offs has always been an inherent part of networking computers together so that they can share files, programs, printers and modems and exchange messages. There are many different ways to do it, although most have characteristics in common.

A hardware port into the machine is required, which can be as simple as the serial communications port that comes standard on most computers or a more elaborate expansion card for the computer’s chassis that provides a special high-speed data path between machines.

(Macintosh users have an advantage over the PC-compatible crowd because Apple Computer builds a network capability known as AppleTalk into the machines.)

Wiring of some sort is usually needed to connect computers. Depending on building codes and the location of the computers, it can be difficult and expensive to string the cables, whether it is simple twisted-pair telephone line or heavy coaxial cable.

Then, of course, there is the software needed to make it all work, which ranges from cheap to thousands of dollars.

The LAWN network overcomes many of these difficulties because instead of cable connections, it uses a special low-power radio transmitter known as “spread spectrum technology.”

Because there is no wiring, the computers can be moved as the need arises without disturbing the network and users are quickly added or deleted.

The ease and flexibility of LAWN comes at the price of slow data transfer speed. Communications run at just 9,600 baud (1,200 characters per second), a snail’s pace compared to a traditional wired local area network that uses an architecture such as ethernet, token ring, Arcnet or StarLan.

(A new version of LAWN due out soon will double the speed to 19,200 baud, or 2,400 characters per second. Contrast that, however, with the 1 million to 2 million characters per second that a good ethernet or token ring network can handle or even the 320,000-character-per-second speed of AppleTalk, which many users consider to be too slow for the large graphics files that Macintoshes generate.)

Nonetheless, for many situations, LAWN offers enough advantages to overcome the slow speed. The reason is its unique design.

An individual LAWN unit, which retails for $495, is a small radio transmitter housed in a beige-colored plastic box about the same dimensions as a VHS videocassette, but twice as thick. It needs electrical power from a cord leading to a small transformer that plugs into a wall socket. Connection to the computer is with a serial cable, supplied with the unit, that will attach to either a nine-pin or 25-pin socket.

There actually are three models of LAWNs, one for computers, another for printers (they must be serial printers, not parallel) and the third for modems. The only difference between them is the cable supplied with the unit.

These three personalities are another aspect that sets a LAWN network apart from the traditional varieties. In hard-wired networks, printers and modems must be attached to a computer on the network and are reached by routing signals through that computer.

In a LAWN network, printers and modems stand by themselves, unconnected to any computer and thus free to give full attention to any computer requesting their services via the radio signal. In a hard-wired network, you can lose access to a printer or a modem if the person to whose computer it is attached turns off the computer, locks the office and goes away. Or your use of such a printer can slow down the other work that is being done on a computer to which it is attached.

The free-standing nature of the LAWN network also means that there is no dedicated file server on the network. In higher-performance networks, it is usually necessary to dedicate one computer solely to running the network and storing the programs and data files that everyone will use. Otherwise, if someone tries to use that computer to run a program, the processing demands of the network will interfere.

While at first it might appear that a LAWN network is more expensive than other types because of the need for a separate device at each shared printer and modem, it probably is no more expensive and may be considerably less when you count savings in file, printer and modem servers and wiring costs.

Installing a LAWN couldn’t be much easier. After you have plugged a unit in, you run a software program to set its configuration and give it a name--LASER or DOT or FRANK--by which any user can recognize it.

Printer and modem LAWNS must be connected to a computer to be configured. Then they are unplugged and moved to the device they will serve. A backup memory in each LAWN lets it remember its configuration for a while after being unplugged. There is also memory enough to store four pages of text if the printer or modem or computer is busy when the data is transmitted.

Several LAWN networks can coexist in the same area because they can operate on four different radio frequency channels. Additionally, passwords can be assigned to create separate groups of users.

Once the network is installed, the LAWN software is used to direct operations. For instance, it is possible to tell the computer to use either the printer connected to your computer’s parallel port, or to any printer with a LAWN attached. If you try to use a printer that is busy, the LAWN will wait until it is free and then print the file.

Using a modem works the same way, but there is a problem with the current LAWN software for modems. You must set the communications parameters--commands that define how the telephone signal will be sent--using the LAWN software, and those parameters cannot be overridden by your communications software. Most of the time that’s OK, but if you use several on-line services, you may encounter situations where they require differing parameters.

Because there is no file server in a LAWN network, you cannot run programs stored on another computer, nor can you reach out to another computer and fetch files from it. All programs you run must be loaded on your own computer, and the only way to get a file from another machine is if that user sends it to you.

Files are sent back and forth as attachments to messages. Messages are very easy to send and receive. The only limitation is that, because of the network’s slow speed, it isn’t practical to send large data or graphics files across it.

Nor is it practical to print any file that has graphics. I found that normal text files printed as fast on a laser printer using the LAWN system as they did when directly connected.

But printing a high-resolution spreadsheet graph from Quattro Pro was a different matter. It took about a minute when cabled directly to the printer, but sending the same graph over the LAWN took eight minutes to print.

So you have to balance your needs when considering LAWN. If you routinely work with short text or data files and want to avoid the wiring hassles of traditional networks, LAWN may be just the answer.

LAWN: A wireless local area network

Features: A small radio transmitter, $495, that attaches computers, printers and modems, allowing them to interconnect without wires. Signals will span 100 feet indoors and easily penetrate walls, doors and even floors.

Requirements: IBM-PC or compatible with a serial port and at least 384 kilobytes of RAM operating memory. A hard disk is recommended.

Manufacturer: O’Neill Communications Inc., 8601 Six Forks Road, Raleigh, N.C. 27615. Phone: (800) OCI-LAWN.