Difference between revisions of "Wiring Considerations"

Revision as of 17:53, 14 May 2008

Introduction

Older, proprietary home automation and security systems traditionally have required their own, dedicated wiring. Placing that wiring is often the biggest hurdle in installing such systems, and usually entails tearing open walls in order to run the special cabling (which is often very thick and difficult to manage).

In contrast, LinuxMCE uses standard CAT5 wiring and RJ45 jacks. Because it is IP (Internet Protocol) based (the same protocol that runs the Internet and most local home and office networks), it runs directly over an Ethernet network. Ethernet networks use standard CAT5 (or sometimes the slightly heavier CAT5e/CAT6) wiring with RJ-45 jacks. This wiring is often already pre-installed in recently-constructed homes, since it is now used for most phone systems as well as for home networks. Even if your home does not already have CAT5 wiring pre-installed, CAT5 wires are some of the smaller, easier wires to install. Installing CAT5 wiring in a house is well worth the cost and will increase the resale value, even without a LinuxMCE system. Home networks (LANs) that are run over CAT5-wired Ethernet connections are increasingly popular for Internet access and file/printer sharing throughout the home.

Thus, the only wiring requirement for LinuxMCE is that you have Ethernet (CAT5) wiring. All wired LinuxMCE devices (such as a PC used as a Media Director) will be able to directly plug into the RJ45 jack.

Wired vs. wireless connections

Note, however, that not all LinuxMCE devices require a wired connection. Many can connect wirelessly, if you have a wireless access point connected to the LinuxMCE Core server. However, it is easiest for the main components, the Core and the Media Directors, to be connected in a wired fashion.

CAT5 vs. CAT5e vs. CAT6

• CAT5 wiring is the smallest gauge. It was the standard for many years and is suitable for data speeds up to 100 Mhz, which was the maximum for many years over LANs. However, the increased speeds and loads of modern LANs place a strain on the characteristics of this wire. It is no longer recommended as the wiring standard.

• CAT5e wiring is now considered the standard, and uses somewhat higher gauge wires. This enables the reliable transmission of data at Gigabit speeds, used by newer LANs. It is also more reliable when longer runs of wire are used.

• CAT6 wiring uses even higher gauge wires. This is suitable for long wire runs.

Using pre-installed CAT5 placed for telephone systems

Obviously, you cannot use the same wire for the telephone system and the LAN. Telephone systems run their own power over the CAT5 lines, in a configuration different from Ethernet devices. If you connect an Ethernet device to a live telephone line, you can burn out the Ethernet device.

However, telephone installations often include redundant CAT5 wires that are not connected to the telephone system. (For example, my home is wired with two CAT5 wires to each location, one connected to a telephone jack and one left unconnected.)

It is very easy to use a redundant CAT5 wire for the LAN by connecting it to an additional RJ-45 jack, which can be added to the same outlet. The wire must then be traced to the other end, which will almost always be at the telephone patch panel for your home (where hopefully it will also be unconnected) and connecting it to the LAN instead. This presumes that you have a router, switch, or RJ45 connection (to the rest of your LAN) to which you can connect this wire (using an RJ-45 connector), at the location of the telephone patch panel.

Ethernet wiring standards

It is important to note that there are two wiring standards for Ethernet, T568A and T568B. My local electrician was clueless about this and wired all my CAT5 connections wrong.

For a quick tutorial, see this guide or wiring Ethernet connections.

Most Ethernet wiring is currently done using the T568B standard, and I highly recommend you stick to it. However, you must be aware of when there are deviations from this standard. For example, my Ethernet-wired surveillance cameras all use the T568A standard. This took me a long time to figure out, and, again, my electrician wired them all incorrectly.

It is tricky to adapt T568A to T568B -- you need a special type of cross-over cable. This is somewhat complex. For the most part, I recommend you just wire everything using the T568B standard.

Also see: What is proper cat5 cabling?