You have a small office. You and your staff frequently have to access and change documents. You all need to update databases, maintain sales contacts, and distribute invoices. Most importantly, you all need to communicate electronically. How can this be done? A local area network (LAN) is the answer. But what should you choose: 10Base-T or Fast Ethernet? Do you know enough to make an intelligent decision?

Pros and cons One simple networking kit that contains two network interface cards (NICs) and a four-port hub. This is enough hardware to connect two desktop PCs, a printer, and a removable-cartridge drive or notebook, for example. Until recently, a small office network would generally use 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 for 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 technology system. Although expensive when first introduced, Fast Ethernet products are nearly equal to the older 10 Mbps products.

So which is the best to purchase? At first glance, it may seem that Fast Ethernet is the obvious choice, since its 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 trait 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 some existing network hardware you're currently using, such as a print server.

If you can't decide or if you think you may need the extra bandwidth in the future, consider the purchase of a system using 10/100 NIC cards and a 10 Mbps hub. This setup is totally 10 Mbps-compatible. So, when you're ready to upgrade to Fast Ethernet, you just change out the hub to a 100Mbps model.

Other choices Although Ethernet and Fast Ethernet are the most economical, fastest, and most widespread networking solutions, you may prefer the flexibility and convenience of a non-Ethernet network, and even prefer to not use wiring at all.

You might want to consider using your phone lines, rather than installing new cabling. 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 DSL (digital subscriber line, a telephone service), 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. You install a 10Base-T card in each PC and then 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 1 Mbps. This is fast enough for sharing printer or 56-Kbps Internet access. Additionally, the company is releasing an internal card version that combines the function of a standard Ethernet card and that of the external Home Run adapter, all on one PCI card.

You also can consider setting up a wireless system network. While wireless products have been sold for years, they've been too expensive for use in a small office. Now, however, one available product uses narrow band microwave frequency transmission in the unlicensed 5.6 GHz band. It covers a 120-ft radius in a typical building or up to 300 ft in unobstructed open space. Although, the components are relatively expensive (list price for a PC card is over $300, and over $400 for a portable PC card), the system is still a real value for anyone who wants to conveniently set up a network that runs at Ethernet speeds. In addition, if you choose to use 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 also can consider setting up a network that uses your building's AC power wiring to easily connect PCs and a printer into a network. As shown in Fig. 4, this manufacturer's technology 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 a software program for sharing your Internet connection. This setup offers a throughput of only 230 Kbps, which is quite slow compared to an Ethernet system. But for simple needs such as file sharing, printing, and getting 56 Kbps Internet access, it's quite adequate.

As with a lot of devices that place low level signals on the 120 V ac wiring in a building, getting reliable performance is a key factor. 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 in the room.

There are other factors you have must consider. 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 turned on for you to send a job to the printer. You might consider investing less than $300 for a printer server, a small device that serves this purpose. You can also invest in a dedicated hardware device that will let 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.