Now may be the time to set up a LAN in your small office. By networking your desktop PCs and laptops, everyone can share files, printers, and peripherals.

You have a small office. You and your staff need to access the same files. This includes updating databases, maintaining sales contacts, and distributing invoices. Most importantly, you all must communicate electronically. How can you achieve this? A local area network (LAN) is the answer. But how do you choose between 10Base-T or Fast Ethernet?

What's out there. Until recently, a small office network generally used hardware based on the 10Base-T Ethernet standard, which uses unshielded twisted pair (UTP) copper cabling as the media connecting each PC to a central point , called a hub. The maximum transmission speed is 10 megabits per second (Mbps), which is generally fast enough to accommodate the needs of a small office.

For a slightly larger LAN with bandwidth-intensive needs (such as moving CAD files or running audio applications), you need a Fast Ethernet, which is a 100Mbps system. Although quite expensive when first introduced, Fast Ethernet products are nearly equal to older 10Mbps products.

Which is best for you? At first glance, you may see Fast Ethernet as the obvious choice, since its network interface card (NIC) is only $20 to $40 more expensive per computer. Because Fast Ethernet allows for greater bandwidth (meaning it provides a wider pipe for pushing data through), it's much faster. This allows for a superior upgrade path when you decide to connect to a fast Internet-access service. However, if you put up a Fast Ethernet LAN today, you might have compatibility problems with existing network hardware, such as a print server.

If you may need extra bandwidth in the future, consider purchasing a system using 10/100 NIC cards and a 10Mbps hub. This setup is 10Mbps-compatible. When you're ready to upgrade, just change out the hub to a 100Mbps model.

More choices. Although Ethernet and Fast Ethernet are the most economical and fastest options for widespread networking solutions, you may prefer the flexibility of a non-Ethernet network. Or you may choose not to use wiring at all. Rather than installing new cabling, you may want to consider using existing phone lines. One manufacturer has what it calls the Home Run Adapter, which piggybacks a network signal over existing wiring; in this case, over your building's telephone cabling. Similar to the telephone service called digital subscriber line (DSL), this technology uses a high-frequency signal telephones can't detect, so the signal doesn't interfere with your phone's or fax's normal operation. All you do is install a 10Base-T card in each PC and connect a small black box with 10Base-T and phone connections on the back and five LEDs on the front. Setup is simple: Plug the 10Base-T connector into the PC, then attach the phone cord into the RJ-11 (or RJ-45) phone jack on your office wall.

Another manufacturer's technology provides Ethernet performance, with claimed throughput of 1Mbps. This is fast enough for sharing a printer or 56-Kbps Internet access. Additionally, the company is releasing an internal card version combining the function of a standard Ethernet card with an external Home Run adapter; all on one PCI card.

You also can consider setting up a wireless network. While manufacturers have sold wireless products for years, they've always been too expensive for small offices. Now, however, one product uses narrow band microwave frequency transmission in the unlicensed 5.6G Hz band. It covers a 120-ft radius in a building or up to 300 ft in an unobstructed open space. Although, the components are relatively expensive (a PC card lists for more than $300, and $400 for a portable PC card), the system is still a value if you want to set up a network that runs at Ethernet speeds. If you choose a special wireless hub (which costs about $900 list), you can have up to 128 nodes and connect them to an existing 10Base-T Ethernet network.

You can also set up a network using your building's AC power wiring to easily connect PCs and a printer to a network. As shown in the Figure, on page 64N, this manufacturer uses an adapter that plugs into an AC receptacle wall outlet and connects to the parallel port cable of your PC or printer. The package also has software for sharing your Internet connection. This setup offers a throughput of only 230Kbps, which is quite slow compared with an Ethernet system. But for file sharing, printing, and getting 56Kbps Internet access, it's quite adequate.

As with many devices that place low-level signals on 120VAC wiring, getting reliable performance is essential. If you set up this power line carrier system and then find it difficult to make a connection from one outlet in a room, the manufacturer suggests inserting the adapter into a different outlet.

To share a printer or Internet connection on a LAN, you must designate a PC to host the device. This means for printers, the PC host must be on for you to send a job to the printer. You might consider investing less than $300 for a printer server. You can also purchase a dedicated hardware device that let's you share an Internet connection without slowing traffic on the network. One such device consists of an analog modem connection and a four-port 10Base-T hub. Another more expensive device has connections for up to three analog or ISDN modems.