Wiring Considerations

Introduction

Older, proprietary home automation and security systems traditionally have required their own dedicated wiring. Placing that wiring was often the biggest hurdle in installing such systems, and usually entailed tearing open walls in order to run the special cables (which was 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 often the somewhat 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 Mb/sec, which was the maximum over LANs until recently. 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. In general 100 Mb/sec speeds can transmit 7 simultaneous DVD quality video streams.

• 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. In general, Gigabit data transmission speeds can transmit 100 simultaneous DVD quality video streams.

• CAT6 wiring uses even higher gauge wires. For standard 250 Mb/sec data speeds (and Gigabit adaptations), it is preferable. It is suitable for long wire runs for 250 Mb/sec (or Gigabit) data speeds. It is preferred over CAT5e for 10 Gigabit data transmission speeds (which is not currently very common in home and small office LANs).

Using pre-installed CAT5 placed for telephone systems

Ethernet and analog phones can easily share the same wiring, assuming you use Cat5 or better for everything. Analog phones use the two center pins of an RJ45 connection (pins 4 and 5, or the blue wires), while standard ethernet uses pins 1, 2, 3, and 5 (orange and green). You should be careful running analog phone service on a line that is actually connected to an ethernet device however - although it shouldn't be a problem, there is no guarantee your manufacturer didn't do something silly that will cause the device to malfunction as soon as the phone rings and 80V AC is sent down the line.

In general, if you use a patch panel in your wiring closet, you can plug your ethernet jacks into either a switch, or analog phone service as required (and generally you do not run them both simultaneously down the same wire). An RJ11 phone plug will fit into an RJ45 jack with no issues. The nice part about using a patch panel is you can reassign jacks as necessary - if you need an analog line into a given room, then you just plug it in at the patch panel and you're good to go.

If you upgrade your phone system to use VoIP, then you are already set as you can easily convert jacks to ethernet by patching them into an ethernet switch. You can even maintain some of your older analog phones by using an analog terminal adapter in the wiring closet, and patching the analog lines to your jacks.

Going further with VoIP phones, it's very popular to power them with Power over ethernet (PoE) from your wiring closet. In this case, you have a PoE capable switch (or injector) connected to your patch panel or cabling, and generally plug it into a UPS to provide backup in case of power failure.

Note that when using PoE or Gigabit ethernet, you cannot share analog phone service on the same cable as ethernet as they both use all 4 pairs.

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 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?