Monday, October 12, 2009

Alternatives to Wi-Fi CAT-5/6 - Updated

Electric Forester's Structured Cabling 10/100 LAN Primer

( scroll to the end for solutions) 

This post relates to both CAT-5 and later CAT-6 Local Area Networks (LAN) cables.

Category 5 cable is typically made of four unshielded twisted copper pairs. The two wires of each pair are designed to carry equal and opposite signals. Any emissions from one wire are counteracted by equal and opposite emissions from the other in the pair. Screened cable and CAT-6 is used in high security or electrically noisy environments or to protect the electromagnetically hypersensitive. The CAT-5 cable feeds CAT-5 sockets around the building that computers and peripherals simply plug into.
Cables have to be installed by someone who knows what they are doing because tight bends and running next to power cables can for example, reduce data transmission speeds. CAT-5 is a mature and well-tried technology and there are many competent installers. The point about CAT-5 is that it is faster than wireless, more secure and safer because the radio waves stay in the wires and are not broadcast. The CAT-5 sockets are wired via a central 'Patch Panel' to a Local Area Network (LAN) switch which acts like a mini telephone exchange, allowing every socket to be connected to every other. You don't need to get bogged down with the detail as this only really needs to be done upon installation and provided everything is labelled properly and a record kept of the connections, its easily managed by someone competent with paper and pencil.
Each computer and peripheral simply plugs into a socket - can be any one, and then users have interconnectivity between computers, printers, projectors etc. Internet access is via a central router that shares the building's Internet connection between those computers that require it at any given time, making best use of available bandwidth. Internet is provided to the building and central router via telephone cable or fibre-optic 'pipe'. Fibre-optics are much faster (Lasers are used to send the data and each colour can carry 157,000 simultaneous phone calls, effectively making the bandwidth unlimited). If you imagine CAT-5 like the water supply to your taps, a fibre optic 'pipe' is like 4-foot water main, so more than you would ever need. Many people think that wireless networks work all by themselves and they don't need anyone to look after them. School computer budgets (as in commercial settings) have to include hardware, software and support otherwise the investment falls into disrepair and become a waste of money. DLANs, which plug into the mains, send radio frequency signals over building electrical wiring. Mains cabling was never designed for this type of use and signals leak out all over the place and dirty electricity throughout the building will be increased. Speeds may also not be what the manufacturers or users would expect. 
As children grow, their total lifetime exposure will inevitably rise. Daily electrosmog levels continue to rise and come from such sources as mobile phones, their masts, broadcast TV and radio stations, satellites, DECT baby monitors and cordless phones, Xbox 360s, BT-Home Hubs, Sky+HD set-top boxes, microwave ovens, wireless boiler thermostats – the list grows daily. Everyone’s world is now awash with man-made pulsed digital microwave radiation so it makes sense not to add to it further in buildings where particularly children spend considerable time.

As well as computers and shared peripherals, you may want some phones! But the phone company won't put phones over structured cabling, and your landlord won't let the phone company run their own wiring round the building.


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