by by Greg Weinstein

Setting Up a Network In Your Small Office

Welcome to the 90s! It's a great time to be automating our offices—we have so many choices. More and more, those choices are going to involve networking our offices. Unfortunately, given so many choices, it's sometimes difficult to decide what to do. You may have heard about the capabilities and possibilities in linking your office PCs together. You may have even been reading up on the subject. Many magazines specialize in networking. You may have also found out the limitations of these sources of information. Simply: much of this information is aimed at the networking of an entire office, business, or firm, dealing with hundreds or thousands of PCs.
September 1998

Last issue, I discussed the goals of this column: to fill you in on how to install a network in a home office or small business. The emphasis is to be on the most practical and cost-effective way to get things done. After all, we don't have the resources of, say, the Computer Support Department at Exxon!

The first subject I started with is your basic decision: what type of wiring to install_your physical layout. The choices available are:

1) Fiber Optics wired in a star,

2) Arcnet coax cable (RG-62) wired in a star,

3) Ethernet twisted pair (say, Category 5), wired in a star, and

4) Ethernet coax cable wired in a bus.

Remember, a "star" is where you run a separate wire from the location of each computer to a central location, where they are each connected into a box called an "active hub", which makes everything work. A "bus" is where you run the wire from one computer to the next, and then to the next, and so forth; it usually doesn't need the hub.

If you were building your office space from scratch, and running wires, and you know exactly where the computers might possibly be located, needed to be able to upgrade to faster network products in the future without rewiring, AND you or your installer know exactly how to install the connectors properly, then you might be better off running Category 5 cable. This is also referred to as UTP_unshielded, twisted-pair. It's high-quality telephone wiring, and you should run either two pair (for standard Ethernet), or four pair (for compatibility with the "fast Ethernet" coming down the pike).

On the other hand, if you are doing it yourself, are running it in your house, are making temporary installations, are working in existing office space, need to be able to easily add additional computers or other accessories, and/or want to do it cheaply, then you want to use Thin Ethernet. This is in the form of RG-58 A/U CL2 coax cable, which is widely available. That's my recommendation_now let's see why and how.

First, it's possible you can wire up your network without fooling with making cables. You can buy made-up sections of Thin Ethernet cabling at some computer stores (even some Radio Shack locations). Moreover, you can buy these ready-made sections from distributors, too. You'll pay more_but save a bunch in terms of the hassle factor. But, let's also keep in mind you might want to make the cables yourself_you can buy a raw spool of this wire for 15 cents/foot, if you shop around. Your only limitation is to make sure that all the different cables you use are the same general type.

There are two different types of this cable. One is called "plenum". It's what the electrical code usually requires when you are running cable through walls and inside ceilings used for an air return space for your air conditioner/heater system. (Look for a grill opening into the wall or ceiling, without anything connected to it on the other side_that's a sure sign that you've got this). Plenum wire costs more_use PVC cable (the cheaper kind) if you are able.

Second, you can go ready-made. If you buy the cable, you should get it with BNC connectors on the ends. These are the same connectors that pros use in commercial video equipment, and are widely available. If you want to build cables yourself, you'll need a crimp tool (about $65), and a stripping tool (about $25) or an X-Acto-type knife. You'll also need a lot of practice on doing it correctly_plan to mess up a half-dozen, practicing.

Be SURE you get the correct BNC connectors for your crimp tool and your wire (O-crimps are the best). And, don't try to use twist-on BNC connectors. True Thin Ethernet cable has stranded center conductors, and works poorly, since little strands of wire pop out and stick in the wrong place! The raw BNC connectors will cost about $3 each_the three-piece works the best. I am NOT going to try to describe the process of making the cables up_that's like trying to describe how you keep your balance riding a bicycle. Try getting the guy who sold you the crimp tool to demonstrate how it works_this is a great reason to go buy it from a local electrical supply house. Remember, improperly attached BNC connectors are usually the reason your network will not work correctly.

If you are going to build your cables yourself, you should also have any old multimeter to test them with_you can get one at Home Depot or Radio Shack for about $10. When you finish attaching a BNC connector, plug it into a T-Connector or Barrel Connector. Then, set the meter to "ohms" or to "continuity check". Take a reading end-to-end on the center conductor, then another reading end-to-end on the outside of the BNC connector (to the braided shield, if you haven't put a BNC on the other end yet). Both readings should read 0 ohms, or continuity (and some meters will beep to indicate this)_a "short circuit". Now take a third reading, between the center conductor and the outside. This should read very high on the ohmmeter, or no continuity_it should be "open". If your wire passes these tests, you have correctly installed the BNC connector. Do this test BEFORE your try to use the wire in your network!

Obviously, you can save a lot of money, but spend extra time, by making up your own BNC cables. But, there is an easier way to install Thin Ethernet, which doesn't require installing BNC connectors at all. But first, a digression.

What's the big problem with Thin Ethernet, which causes big companies to bypass it and go with UTP? Three things. The first is that there is a maximum length of cable that you can use. You don't have to worry about that one in home office or small business installations. The second IS a problem_how do you keep someone from accidentally unplugging a BNC connector somewhere, and thus disabling the whole network, messing up whatever work any and all computers are processing when this occurs? Finally, as we shall see later, Thin Ethernet MUST be wired from computer to computer. This can look sloppy; you really wanted to run one wire from a jack in the wall to your computer. New technology has solved these problems, as well as totally eliminated the need for BNC installation.

I refer you to the AMP Lan-Line Thinnet Tap System. AMP is one of the largest companies involved in connector technology, and they have a division dedicated to networking products. They are distributed by many companies in every city, including major national electrical distributors (such as Graybar). They also have an number for free assistance, free catalogs, technical notes, and referrals to your local sources: 800-522-6752. They sell everything you need for the old-fashioned BNC-connector installations. But, they came up with the Thinnet Tap System to simplify our lives_and solve the problems mentioned above.

With this system, you run the wire in walls, from wall-box to wall-box. In each box, you install a Tap Assembly. Installation is easy_it only requires a penknife and screwdriver. It's almost foolproof_you still need to test the finished wire end-to-end as mentioned above, after installing the taps. Installation of each tap takes under 5 minutes, and the kit of parts costs about $15/location. That eliminates the need to fool around with BNCs and crimp tools. Once the tap and the wall plate is installed, you have a jack to plug a computer (or other Ethernet accessory) into.

What's really nifty about this system is the special cables. They plug into the jacks and run directly to your computers. The way they are engineered, you can plug or unplug them from either end without breaking the Ethernet and bringing down the network. Better, you can buy test cables, test boxes, and even extension cords (with two or four jacks at the end of them), so you can plug, unplug, move things around, even add more computers. The only drawback to this system is the unusual high cost for the special cables_around $38 for an 8-foot length. Still, figuring the savings in time, energy, and neatness, there's a lot to like about this system. If you're wiring a small business office permanently, this is likely the best choice.

If you like the drop cable effect, but don't want to make a permanent installation, AMP also sells special cables which run from your Thin Ethernet cable, to the back of your computer. If you have pre-made BNC Ethernet cables, you get the effect of your main cable running along the wall, with a junction every now and then, with this special "drop" cable running to the PC. It really has, effectively, two pieces of coax running in a loop under a single cover, but it looks neat.

Don't forget_if you buy your Thin Ethernet cable already made up, or if you make it yourself by adding BNC connectors, you can always just run it directly from PC to PC. If you just have (say) two or three computers in your basement, this is surely the simplest method.

To conclude: use Thin Ethernet wiring, according to the 10base-2 standard. That's RG58 A/U to you, available in plenum or the lower-cost PVC jackets. You can make up your cables to length, which is an acquired skill, or buy them ready made. You can run them from computer to computer_it works fine, but can look messy. For permanent, in-wall installation, consider the more-expensive AMP Thinnet Tap System, since it solves a lot of problems, looks really professional, and is near foolproof after installation and testing. Next time, I'll conclude this discussion by describing the few, simple rules you need to know to install Thin Ethernet so it works first time, every time.

Six Easy Lessons

Here's how to set up a simple network in your small office.

- Setting Up a Network in Your Small Office

- What Type of Wiring to Install

- The Rules for Thin Ethernet

- Selecting Network Cards

- Installing Those Ethernet Cards

- Some Server Decisions

Setting up a network, networking for a small office, small office network, simple networks - are all covered in these tutorials.