Tuesday, March 25, 2008

DS3 Over Copper Avoids Fiber Installation

Fiber optic connections are the high bandwidth solution that every business wants. That is, until they get the bill for trenching new fiber from the carrier POP (Point of Presence) to their location. Depending on how far out you need to go, the construction costs alone can be in the tens to hundreds of thousands of dollars. Maybe more. Don't assume that you're stuck with high fiber costs or low speed lines until you look into DS3 over Copper.

But, wait a second. DS3 is a fiber optic line service. Right? Yes it is. But before that it was delivered on T3 coaxial copper lines, waveguides or microwave transmissions. DS3 or Data Service level 3 is simply a specification for a 45 Mbps TDM protocol that can ride on whatever carrier is available. The newest approach is to go back to tried and true copper wiring with new modulation schemes.

Why go back to copper after all the technology advancements that have given us Gigabit bandwidths on fiber strands? The answer gets back to price and availability. In fact, price is usually driven by availability. For all the high-tech ballyhoo and industry concerns about overbuilt and unlit fiber, just the opposite is true in most areas. Sure, the high traffic corridors between major metropolitan areas are flush with dark fiber. The undersea routes were the same way for years. Recently a lot of that fiber is being pressed into service, as video and other high bandwidth applications sop up all the packets they can get. Most smaller population and rural areas have no fiber access at all. The only glass in the ground is on its way somewhere else.

Copper, on the other hand, is everywhere you look. Thanks to over a hundred years of telephone system build-out, there is hardly a building anywhere that isn't already wired for at least a couple of pairs of copper. Most business locations already have multi-pair binders to support their telephone systems.

This copper that is so desirable is ordinary twisted pair copper wiring that you find underground or overhead. Conventional thinking was that these "phone wires" are only good for audio frequencies. But DSL services showed that it's possible to transmit multiple Mbps of data over those simple unshielded cables. T1 lines are provisioned on two pair of standard telephone line copper. T1 can be extended almost indefinitely with signal regenerators every mile or so.

But T1 lines are spec'd at 1.5 Mbps. How do you get DS3 over copper? Fractional DS3 bandwidths can be obtained by simply bonding multiple T1 lines together, which gives you the sum of their bandwidths. In other words, 4x T1 bonding gives you 6 Mbps. You can often get up to 10 - 12 Mbps with this technique. If you have a T1 line now, you can probably get bonded T1 service to increase your WAN bandwidth.

The demand for high bandwidths in areas not served by fiber optic carriers has given an impetus to developing new approaches to squeeze more Mbps from each copper pair. Aktino's AK3000 platform gives carriers the option to offer DS3 over copper using multiple pairs. The technical approach uses DMT (Discrete Multi-Tone) modulation and MIMO. If MIMO sounds familiar, its because Multiple Input Multiple Output is the antenna technology used to speed up WiFi networks in 802.11n access points. Aktino has applied a similar approach over wireline to counter the problem of interference between pairs in a binder group.

Pulse Communications, Inc. has a product called DS3 Express that will convey full rate DS3 connections over 4 pair of copper up to about a half-mile, or a mile with a repeater. A standard type 400 circuit-pack module is used at each end of the circuit to make installation easy.

DS3 over Copper and Ethernet over Copper are two high bandwidth services currently available for business locations not currently lit for fiber. Could your business benefit from an increase in dedicated Internet, high capacity telephone, or private data line bandwidth? See what high bandwidth wireless and wireline service options are available for your location. You may be pleasantly surprised by how little you'll have to spend.

Click to check pricing and features or get support from a Telarus product specialist.

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