Washington Apple Pi

A Community of Apple iPad, iPhone and Mac Users

How to Wire Your Home for Ethernet

By Rick Rodman

Washington Apple Pi Journal, reprint information

Huge numbers of iMacs, PowerBooks and G4s are being purchased today as personal machines for the home. Corporations may dictate platform uniformity, but when people have a choice, they often choose Mac. And Macs, since day one, have come with networking and sound built-in, not just in a hardware sense, but well integrated into the operating system.

Networking a Mac can be as easy as plugging a "swapped" cable into each machine's Ethernet port. By the way, we mean a CAT-5 or CAT-3 Ethernet patch cord with swapped pairs. The pairs are not assigned concentrically, but in a somewhat odd fashion, so you can't use an inverting coupler; inverting couplers and flat "silver-satin" wire is for ISDN and other types of telephone use.

The next step is to get a small, inexpensive hub and connect two or more machines, and maybe a printer, into the hub. There's no configuration to do, just plug them in and use it. Of course, the wires are a little messy, especially when they go from room to room. Again, if your cables are too short and you want to extend them, beware of the cheap couplers at Radio Shack. They're for telephone use and typically swap the entire cable, which is no good for Ethernet - unless you have two of them in the cable, connecting three short cables into one long cable.

This article is for folks who are ready for the next step - permanently connecting their machines in multiple rooms. We're going to cut holes in drywall and drill holes and punch down cables just like the professionals.

Tools and supplies you'll need:

  • 110-type punch down tool
  • Fish tape
  • Spool of CAT-5 cable (shielded twisted pair, 4 pairs, color-coded)
  • Wall plates and RJ-45 jacks with color-coded 110-type punchdown connections
  • Electric drill (and maybe an extension cord)
  • Wood-boring auger bit, 1/2î or bigger
  • Flashlight
  • Some thin, strong wire or string, about 30 feet
  • Measuring tape
  • Hub or switch (see below)
  • Patch panel or 110-type punchdown block with RJ-45 connectors (see below)
  • Two people

Hub or switch?

A hub is a passive device that allows only one device on the network to talk at a time. An Ethernet switch, by contrast, is actually a type of router that allows multiple devices to be talking at the same time. On a hub, all devices must be running at the same speed; a switch can do automatic speed conversion. So you might say, a switch is completely better in every way, right? And you'd be mostly right. The only problem you're likely to encounter with a switch is "hunting," where both the device (say, your G4 Cube) and the switch are trying to autodetect the speed, and both keep switching speeds to try to match each other, and they never manage to agree.

Nevertheless, if you're going to all this work and expense, be forward-looking. Using CAT 5 wire ensures you can run both 10mb/s and 100mb/s; using a switch allows you to intermix fast and slow computers on your LAN, so you can gradually transition your network into the fast lane.

Locating the hub

The goal is to put jacks in the walls, about 18î from the floor, all wired to a centrally- located hub. So, the first decision to make is where to put the hub. Ideally it will be in a room which is not fully drywalled, which is not very crowded, and where a large bulk of wires will not be considered unattractive. In my house there is a laundry room which has no drywall (the walls are not "closed"), and has easy access to a small attic.

If you can find one, a nice thing to have is a 110-type punchdown block prewired with RJ-45 (8-pin modular) jacks. Some with jacks are even color-coded! If you've got lots of money you can get a patch panel with 110-type punchdown positions designed for this job. The wires to the rooms can be punched down, then short patch cords used to connect to ports on the hub. If you can't find one like that, you'll need to crimp ends on the cables coming from the walls -- something I'm rather leery of.

The color coding

The pairs of the signals in the wires are color-coded thusly: blue/white and white/blue, orange/white and white/orange, green/white and white/green, brown/white and white/brown. The first named color is the main color, the second color is a stripe around it, so the first pair is blue with a thin white stripe and white with a thin blue stripe. Only two of these pairs are used for 10baseT; all four are used for 100baseT.

The wall plates

The wall plates that are easiest to use have three main components. First, there is a plate that has a square hole accepting a modular plug-in. Then, there is the RJ-45 jack itself that plugs into the square hole. Get one that is color-coded in accord with the previous paragraph and can be punched down with the 110 tool. Finally, there is a piece that functions as a box. I prefer the metal kind - you push it into a hole in the drywall and bend some large U-shaped tabs around to hold it in place. You can also get what's called an "old work box." The old work box gets pushed into the hole in the drywall; you then tighten bolts on either side which press tabs against the other side of the drywall. You do not need a complete enclosure, because the data wires are low-voltage.

Getting into the walls

The easiest walls to get into are ones that have drywall on one side only. You can cut a hole with a knife or sabre saw, mount the box, punch the wire down on the connector, push it into the plate, bolt it to the box, and voila. This will work, for example, in the room adjoining the room where the hub is mounted.

To get into a closed wall, you need to be able to get to one side of the wall from somewhere you can drill. The basics of wall framing are: a 2x4 across the bottom, a 2x4 across the top, and vertical 2x4's, called "wall studs" spaced every 16 inches center-to-center, or "on center." You can find where the studs are with a stud finder, or by tapping the wall, or by looking for visible nails.

We'll start with an upstairs interior wall. From the attic, find the top of the wall. You may be able to measure from a common point, or it may be apparent from electrical wiring going down, or by a piece of wood at the top, or edges of the ceiling drywall. Down in the room below, identify a nice place for a jack, away from the electrical wiring, centered between two studs, and make a small hole 18î from the floor. Measure from an easily identified reference point - say, the corner of the room - to the new hole. In the attic, measure the same distance from the same reference point and, using the auger bit and electric drill, drill through the wood down into the wall. Have your assistant below shine a flashlight into the hole in the room, and see if you can see it from the hole above. If there is no insulation, you'll be able to see the light (that's why I suggest interior walls).

If you don't see the light, there may be a firestop - a horizontal board running between the two wall studs. This is unusual in interior walls. If you know they're there, you can use drill extensions and other expensive tools to get through - or you can mount your jacks above the firestop, which is much easier.

Now you have verified the holes, enlarge the lower hole to the rectangular shape needed for the bendaround box or the old work box, whichever you have. Poke the fish tape down through the upper hole slowly until your assistant grabs it through the lower hole. Have your assistant tie the string or thin wire to it. Pull it back up through the upper hole. Now tie the CAT-5 cable to the string or thin wire, and have your assistant pull it back down through the lower hole, with about 12 inches of slack. Go down to the room, punch down the jack and mount it as above.

How about downstairs rooms? It's considerably harder, but the technique is basically the same, just from underneath instead of above. The reason it's harder is because of two things: first, there are floor joists going across the floor; second, the subfloor beneath the walls makes it difficult to identify where the walls are.

One technique that you can use for the difficult cases is to make a hole on both sides of a wall - or floor to ceiling - and put a plate on each side with a short piece of CAT5 between them. Walls are usually only 3-3/4î apart - the width of a 2x4; floor to ceiling below is from 8 to 10 inches.

Workstation cables

You can get a crimping tool and make your own workstation cables, by crimping the ends on. Note, however, that if you have a patch panel or punchdown block with connectors as described above, you can use premade workstation cables. They cost more, but poor cable connections are one of the leading problems in small LANs. I strongly advise getting premade cables. Micro Center has them in a variety of lengths and colors. Sure, it's more expensive than making your own cables - but if you have a problem, how valuable is your time?

Your Growing Network

To connect a DSL modem or a cable modem to your network, you'll need a swapped cable to connect it to your hub or switch. Next, you may want to add a router so that multiple machines can connect to the Internet at a time. When you get your next printer, look for an Ethernet connection with AppleTalk and TCP/IP support, plus Postscript, of course. Keep a notebook with records of how each machine is configured, with addresses, interfaces and other notes for quick reference. Share your printers, and set up shared folders on each computer. Think about your naming convention: if you name a computer after its user, what happens when that user gets a new computer and passes the old one on to someone else?

AppleTalk is a networking protocol that works with very minimal management. Still, don't think of a network as something you set up once and forget. A network is not a static, unchanging thing like a mountain - it's always growing, changing, adapting, like a tree. It may take a little extra care and nourishment. But once you have a network, you can't go back to the old way of doing things - it's that much different, and better.