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(Passive Optical Network) An optical point-to-multipoint access network. There are no optical repeaters or other active devices in a PON, hence the name "passive." PONs are designed for local loop transmission rather than long distance and serve to bring fiber closer to the customer in order to obtain higher speed. PONs began in 1995 when a group of telecom providers organized the Full Service Access Network group (see FSAN).

An optical line terminal (OLT) device resides in the telco central office or cable company head end. It generates or passes on SONET and DWDM signals via fiber to an optical network unit (ONU) in the field. The ONU provides the optical to electrical (O-E) and electrical to optical (E-O) conversion between the fiber and the copper wires that reach homes and offices in a "fiber to the curb" (FTTC) or "fiber to the neighborhood" (FTTN) scenario. When the optical line goes directly into the building for "fiber to the home" (FTTH), an optical network terminal (ONT) is used to terminate the fiber. Fiber to the home is also called "fiber to the premises" (FTTP).

APON (ATM PON) was the first passive optical network and uses ATM for transport. BPON (Broadband PON) includes APON, Ethernet and video transports. GPON (Gigabit PON), which uses the SONET GPF frame, is designed to be efficient for packets as well as TDM. BPON and GPON are the ITU-T G.983 and G.984 standards respectively. EPON is the IEEE Ethernet standard for PONs.

Passive Optical Networks
PONs provide a way to bring high-speed fiber networks closer to the customer in the local loop.

BPON     GPON     EPONITU-T    ITU-T    IEEEG.983    G.984    802.3(Mbps)            (Gbps)ClassesSupported    B,C      A,B,C   PX10/PX20**

 Downstream   155    1.25 Gbps    1.25
 Speeds       622    2.5  Gbps

 Upstream     155     155 Mbps    1.25
 Speeds       622     622 Mbps
                     1.25 Gbps
                     2.5  Gbps

   Maximum Number of ONTsBased on Class and DistanceODN CLASS    7 km    10 km    20 km

   Class A       16      13       6
   Class B       40      32      15
   Class C      101      81      39

  ** PX10 & PX20 are similar to B and C
References in periodicals archive ?
Embassy in Dhaka provided a grant of $52,000 to APON for a new rehabilitation center for female drug addicts, which opened in November 2009.
APON * BPON * EPON * GPON * Optical components * Transceivers * OLT controllers * ONT controllers
beyres hit wryttyn apon hym and he were put in a fyr to be breynt or hongud on a tre he schould not dey wyll hit is apon hym'.
Specific components covered include VDSL-1, VDSL-2, APON & BPON, EPON, GPON (transmission); and MPEG-2, Windows Media 9/VC-1 and MPEG-4/H.
in a dysh of pe charlet & poure pe [c]reme apon it; and medyl sugure, sawndyrs, & masz togydere & strew it peron & serof it forth.
Embassy in Dhaka has about $52,000 available from previous years in narcotics assistance funds that it plans to provide to APON to improve its facilities for rehabilitation of female drug addicts.
APON and other NGOs have expressed concerns about new regulations imposed on treatment facilities by the GOB.
K-Micro's new fast-lock CDR technology is for use in developing fiber-to-the-premises applications, including GPON, EPON, BPON and APON.
The PON OLT Hardware report tracks APON, BPON, EPON, and GPON OLT hardware.
McDATA fit the bill perfectly, providing the availability, flexibility and data replication capabilities, and helped BNG optimize value and high return on investment," said Fred Apon, infrastructure specialist at BNG.
Asia is the major action point for PON, where NTT West in Japan continues with its BPON rollout, and tens of thousands of PON subscribers deployed APON and EPON in 2003 and 2004.