The New Structured Wiring

New? Yes, I would say new. With the evolving technologies it is time to rethink structured wiring.

Structured Wiring Defined
Structured wiring is basically where a bundle of cables is brought back to a central enclosure from each location for a TV, telephone or data port. In the case of a TV location this usually will involve RG6 coax as well as cat5e cables for data/telephone use. In addition to the TV locations there will be also other telephone/data port locations scattered about the home. They also will run from the wall plate back to the structured wiring central enclosure, so that with every wall plate you know where the other end of the cables will be. This is opposed to the older technique of wiring from wall plate to wall plate in a daisy chained configuration. While daisy chaining may work fine for telephone cable, with RG6 for TV use it becomes very limiting to OTA or cable use. Satellite receivers need isolated coax between the receivers and the dish or multiswitch. Multiswitches are located in the central wiring enclosure. Even with OTA and cable TV use the daisy chaining can cause the end devices to be starved for signal as each splitter will cause additional signal loss. Also splitters tend to be hidden inside of walls and forgotten and that will make the coax useless for satellite TV use. With structured wiring everything originates from a common wiring enclosure with no taps or splices as the cables run to the wall plates, so you know exactly how every run is wired.

Current Thinking
Currently when we talk about structured wiring we usually think of a bundle (or separate cables) of 2 RG6 coax and 2 cat5e cables. There are specialized bundles with this complement of cables for structured wiring applications. The reason for the two coax could be for cable and a over the air (OTA) antenna. If satellite is used then the two would be used for satellite and a OTA antenna. Both cases would require 2 coax cables. The two cat5e cables would be for telephone (required for satellite receivers) and a data port that could be used for a Home Theater PC (HTPC) that is becoming more and more prevalent these days with the multimedia PCs. Each cat5e cable will have 4 pairs of twisted wires and since telephone only takes 1 pair per line and a data port takes 2 pair, there will be several pairs left over. This may seem like overkill, but the extra pairs is actually very inexpensive, so the industry has pretty well standardized on the 2 cat5e.

New Thinking
The new thinking is to start off with the addition of 2 fiber optic cables to the structured wiring bundle. Currently there is not much need for fiber inside the house, but in the near future it will be required for a new technology called Internet Protocol TV (IPTV) that will allow TV on demand, even High Definition TV. Many neighborhoods are currently being cabled with fiber all the way to the houses, called Fiber To The House (FTTH), in preparation for IPTV. When this is rolled out for the masses, you will be able to request your regularly scheduled shows that you may have missed over a 48 hour period, or so. It will be like having a Digital Video Recorder (DVR) on every channel that will save every show for 48 hours! Fiber will be needed to allow for this and other future capabilities.

But recent changes in viewing habits has caused some of us to rethink what is required for structured wiring. With the increasing popularity of the DVRs, like the TiVo, on satellite services, the quantity of RG6 cables has become inadequate. Each satellite DVR requires 2 coax feeds from the dish or multiswitch, one for each tuner in the DVR. DVRs are equipped with two tuners so that you can watch one channel while recording another. Now you don’t have to supply both tuners for the DVR to operate, but most people will want the full function out of their DVR. As it can be seen, the two tuners have used up the two coax cables in our structured wiring bundle. This means we would have to diplex the OTA signal off of one of the satellite coax feeds, which is not as desirable as a separate OTA cable. This brings up the possibility of needing another RG6. My preference is to run a second structured wiring bundle of 2 RG6 and 2 cat5e cables to each location that may have a HDTV installed later. This very well may be every TV location in the home, but remember wiring is much less expensive before the walls are closed in.

Other considerations that I have run into is the need for a third satellite feed to run a second receiver for the use of PIP. In order to show a second channel in the PIP window, a separate source is required, hence the second receiver. Some people use the SD receiver the had when they upgraded to HD and pay the extra $5 per month for service, just to have the PIP operational. Other installations have involved a separate surveillance CATV system that allows the selection of various cameras through the NTSC (analog) tuners. This can be done through the 4th coax with the modulators located back in the structured wiring enclosure, or adjacent equipment rack or cabinet.

The bottom line for TV locations to future proof your house would be to run a 2 coax+2 cat5e+2 fiber structured bundle plus a 2 coax+2 cat5e structured bundle.

Now there is another issue in providing wiring for satellite dish service to the structured wiring enclosure. With the old SD satellite wiring there was only 2 RG6 coax cables required between the dish and the wiring enclosure. A third coax was usually added for the OTA antenna. These days with the HDTV dish a probability, 2 more RG6 coax cables need to be furnished for a total of 5 coax cables between the dish/OTA antenna location and the structured wiring cabinet.

Finally, the new AT9 dish system will not allow for diplexing the OTA antenna signal on the satellite cable, so there is a need for a sepatate coax to deliver OTA. With four coax cables this will allow for 2 to service a DVR, 1 for the OTA antenna and 1 for cable or another satellite receiver for PIP or an international satellite receiver. Extra cat5e cables allow for remote IR wiring as well as telephone and internet. Fiber cables will future proof your installation.

Edit: Directv has started using their SWM (Single Wire Multiswitch) systems that allow both tuners and the OTA signals over a single coax. That could moderate the thinking a bit, but due to the low cost of a cable or two, for future proofing I don’t think it should moderate it much.

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