FTTH [Fiber-To-The-Home] Optical Pipes

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There are many kinds of FTTH [Fiber-To-The-Home] (curb or building or anything) systems. Some use PON [Passive Optical Network] systems (less electronics) by using different physical optical fibers for different services.

For example, one fiber is for video television distribution and another separate fiber for bi-directional (two-way) data and voice services. There are multiple receive antennas as they are aimed at different geo-stationary (rotate at the same speed as the earth to remain in the same stationary place) satellites because various television programs are on different satellites. The “headend” contains television channel receivers and main amplifiers. The headend may also contain the NOC [Network Operations Center] for diagnostic testing and signal analysis. See other TECHtionary tutorials for specific CATV terms. Electrical signals from the headend are converted into optical signals through an OADM [Optical Amplifier Division Multiplexer]. In many newer PONs, to reduce points of failure, electrical outages and repair costs, there are no or few OADM amplifiers between the Headend and the customer premise equipment or CPE. Where OADM or optical amplifiers are needed, various types of optical “xboxes or crossboxes” (to connect between cables) are installed. In addition, these installations can be co-located with twisted-pair copper DSLAM [Digital Subscriber Line Access Multiplexers] and other devices.

FTTH (curb) systems use various types of PONs (less electronics) by using different optical frequencies for different services. In some systems, four feeder optical cables serve a PON Cabinet. Typically, PON Cabinets serve up to 128 customers with two-fibers each. Customers can be changed or migrated from twisted-pair or coaxial copper connections by changing connectors. The ONT [Optical Network Terminal] is the point of interface between the telephone network and the home. Attached to the outside of the customer premise, the ONT terminates the optical signal (over fiber) and converts it to three electrical signals (voice, data, and video).

CSWC [Centralized Structured Wiring Cabinet] is a common interconnection or interface location for communications wiring in the home such as TP [Twisted-Pair], UTP [Unshielded TP], CAT5/e [CATegory 5-Enhanced] multi-twisted-pair LAN [Local Area Network], BPL [Broadband over Power Lines], Wi-Fi [Wireless-Fidelity], Coax [Coaxial] cable and optical fiber. The signals are transmitted from the ONT to the CSWC and then distributed from the CSWC throughout the house. In some cases, multi-protocol (TP, coax, etc.) interface is provided by a RG [Residential Gateway].

There are generally three types of cable wiring types used to provide service to the home:

• Quad or 4-wire used with a RJ-11 for telephone.

• CAT5e TP used with a RJ-45 jack for voice and data service.
• RCA plug with RG-6 75 Ohm coaxial cable that is used for video service. According to Qwest, “the home owner discusses with the builder where and how many jacks (for voice, data and video) should be placed in their home.”

Wall Jacks are physical extensions of the ports in the CSWC [Centralized Structured Wiring Cabinet] to the rooms in the house where the homeowner plans to use the phone, computer and/or TVs. There are several varieties: universal jack for video and data; phone & data jack for voice (RJ-11) and high-speed Internet access RJ-45), including wireless; and blank jack for future services. The rest of the animated TECHtionary tutorial will review CATV systems. For example, older CATV systems were designed for one-way broadcast downstream television distribution.

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[tags]ftth,optical pipe,catv,cswc,noc[/tags]