|Home||Reviews||Tools||Forums||FAQs||Find Service||ISP News||Maps||About|
how-to block ads
1. General Questions
If you look closely at a single optical fiber, you will see that it has the following parts:
Hundreds or thousands of these optical fibers are arranged in bundles in optical cables. The bundles are protected by the cable's outer covering, called a jacket.
Optical fibers come in two types:
Single-mode fibers - Used to transmit one signal per fiber (used in telephones and cable TV)
Multi-mode fibers - Used to transmit many signals per fiber (used in computer networks, local area networks)
Some optical fibers can be made from plastic. These fibers have a large core (0.04 inches or 1 mm diameter) and transmit visible red light (wavelength = 650 nm) from LEDs.
"How Fiber Optics Work", HowStuffWorks
(»www.howstuffworks.com), by Craig C. Freudenrich, Ph.D.
HowStuffWorks, Inc., 2002.
fiber lengths can be used as voltage or temperature sensor. Pl Visit the link: http://www.fiberopticinstrument.com/papers/pdf/Fiber%20optic%20intrinsic%20voltage%20sensor.pdf
Because of these advantages, you see fiber optics in many industries, most notably telecommunications and computer networks.
why do I feel sick passing under the newly installed fiber optics cable in my neighborhood?
* fibers are minimum EMI/EMC corrupted. * Different FOS and in fiber communication devices are possible with mm/sm fiber. For more Details about in fiber amplifier follow the link: http://www.fiberopticinstrument.com/papers/pdf/RTEE-10-A23.pdf
I don't know if this is old information, or if it's based on having work done by a commercial contractor or what, but it seems extremely out of date considering you can buy a 100 meter roll of dual multimode fiber with preattached LC connectors for under $100 on eBay, and we just picked up two brand new media converters with the LC modules for $115 apiece. Considering that copper is going up in price and simply doesn't work well on runs that even approach the theoretical 100 meter maximum (particularly buried underground runs, and more particularly after there has been a nearby lightning strike), I would say that it may be cheaper in the long run to just run fiber than Cat 5e underground, unless one lives in a place where lightning never strikes. In any case, unless I'm missing something here, the "low six figures for 100 feet" is ludicrous beyond belief! Perhaps there is a need for a separate FAQ for home/SOHO fiber. Just as 10Base-T and 100BaseT wired networks are considerably different from DSL (even though both use copper wires), using fiber to connect a couple of nearby buildings is far different from a 50 mile commercial fiber circuit. And believe me, there is not nearly enough information out there for do-it-yourselfers that are trying to do their first fiber run - I'd love to find even ONE good page on the subject.
"Fiber to the Curb" (FTTC) refers to the installation and use of optical fiber cable directly to the curbs near homes or any business environment as a replacement for "plain old telephone service" (POTS) Fiber to the curb implies that coaxial cable or another medium might carry the signals the very short distance between the curb and the user inside the home or business.
"Fiber to the Home" (FTTH) is a network technology that deploys fiber optic cable directly to the home or business to deliver voice, video and data services. By leveraging the extremely high bandwidth capacity of fiber, FTTH can deliver more bandwidth capacity than competing copper-based technologies such as twisted pair, HFC and xDSL.
Fiber to the home is deployed in two primary architectures - point-to-point and passive optical network (PON). While both have their place in solving the last-mile bottleneck, a point-to-point architecture is generally deployed to businesses in metro and urban areas, while a PON is a more cost-effective solution for small- to medium-sized businesses and residences. A PON architecture allows a single fiber from the central office (CO) or headend to be split up to 32 ways, delivering high-bandwidth converged services to multiple residences or businesses, using a single optical transceiver in the CO. In a point-to-point configuration, an optical transceiver for each subscriber is required in the CO, thus substantially increasing the total cost of deployment.
"Fiber to the neighborhood" (FTTN) refers to installing it generally to all curbs or buildings in a neighborhood. Hybrid Fiber Coax (HFC) is an example of a distribution concept in which optical fiber is used as the backbone medium in a given environment and coaxial cable is used between the backbone and individual users (such as those in a small corporation or a college environment).
DFITL is in short adsl over FITL (fiber in to loop/fiber to the curb). The way it works is it sends the dsl signal over fiber to the ONU thur the DISCS system and connects to the ATM in the CO. The card in the ONU acts like the DSLAM since the signal runs over copper from the ONU to the house.
IFITL is an implementation of FTTC by Marconi Communications which delivers integrated voice, Digital TV, and high-speed data (PCDATA).
PCDATA which is simply 10Mbps Ethernet delivered to your doorstep. You can't buy "PCDATA" itself because there are no tarrifs for that class of service. Instead Bellsouth sells a throttled version (1.5Mbps down/ 256Kbps up) of PCDATA as "Fast Access". Some call this "DSL over Fiber", but this is a misnomer as there is no DSL signalling involved at all...it's Ethernet, period.
FITL = IFITL without the video and data services (e.g. no PCDATA).
If you are in the unfortunate circumstance of being located in a sub-division serviced by FITL, you are ironically, at a major disadvantage. Remember, DSL requires copper cabling, a DSL modem in your home AND a DSL modem on the other end of the copper (a DSLAM). Since FITL pushes fiber to the curb, the only copper that exists is between your home and the pedestal....and their ain't no DSLAMS in the pedestals.
An HFC network works consists of a headend office, distribution center, fiber nodes, and network interface units.
The headend office receives information such as television signals, Internet packets, and streaming media, then delivers them through a SONET ring to distibution centers. The distribution centers then send the signals to neighborhood fiber nodes, which convert the optical signals to electrical signals and redistributes them on coaxial cables to residents' homes where network interface units send the appropriate signals to the appropriate devices (i.e. television, computer, telelphone).
An HFC network provides the necessary bandwidth for home broadband applications, using the spectrum from 5 MHz to 450 MHz for conventional downstream analog information, and the spectrum from 450 MHz to 750 MHz for digital broadcast services such as voice and video telephony, video-on-demand, and interactive television.
SONET OC levels:
OC1 - 52mb/s
OC3 - 155mb/s
OC12 - 622mb/s
OC48 - 2.5gb/s
OC192 - 9.6gb/s
OC768 - 40gb/s
You can divide OC circuits into what are called STS channels, or tributaries. Generally each OC level has a corresponding STS level, and higher bandwidth optical equipment can carry more than one STS channel, such as a combination of any of the following:
VT-1.5 = T-1 (1.44mb/s)
VT-2 = 2mb/s
OC-1 = STS-1 (usually used for DS3/T3)
OC-3 = STS-3c or STS3 (3 STS1 channels)
OC-12 = STS-12c or STS12
OC-48 = STS-48c or STS48
OC-192 = STS-192c or STS192
OC-768 = STS-768c or STS768 (have not encountered these systems yet)
STS-3c = STM-1
STS-12c = STM-4
STS-48c = STM-16
STS-192c = STM-64
The "c" in STS3c or OC3c stands for concatenated, meaning that the entire 155mb/s is dedicated to one channel (one payload), unlike an STS3, which would be 3 STS1 channels (3 payloads). For instance, on an OC12 ring, you could have 9 STS1 channels and 1 STS3c channel, or 3 STS3c channels and 3 STS1 channels. Once the channels are demultiplexed, they are split into tributaries, the lower-bandwidth interfaces used for connecting to other networking equipment.
Each OC level can be a ring interface to a UPSR (Unidirectional Path Switched Ring) or BLSR (Bi-directional Line Switched Ring). On these rings, generally one line goes east, and another west. If one side fails, individual STS channels (UPSR) or the entire line (BLSR) can be switched to the other path or span, depending on the technology.
thnx for such a detailed info....