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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
Copyright © 1981-2019 by The Computer Language Company Inc. All Rights reserved. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher.
References in periodicals archive ?
El primero corresponde a especimenes principalmente lisos, pertenecientes a las localidades de la laguna de Gran Eneal, laguna Las Peonias, Capitan Chico y desembocadura del Rio Apon. El segundo, de escultura estriada, y el tercero de escultura estriada-espinosa (Fig.
* ATM based PON (APON): was the first PON system which uses ATM as its bearer protocol.
Figure 2 highlights the critical parts of an FTTH asynchronous transfer mode PON (APON) that carry voice and data downstream via the 1,490-nm (red) path and upstream at 1,310 nm (green).
For example: To suffre the thing for Christes fayth / that we worldly wrechid folys wene were vilany and shame, the blessid apostles rekenid for greate glory / for they when they were with despite and shame scourgid, and there apon commaundid to speke no more of the name of christ / went ther way fro the councell ioyfull and glad, that god had vouchsafed to do them the worship, to suffer shamfull despite for the name of Ihesu.
More in line with medieval iconographic tradition, in the Cornish Meriasek, Constantine for his role in persecuting Christians is afflicted by leprosy, effected by "a visour aredy apon Constantyn ysface" (s.d.
Incipit, compiler: 'Quomodo Dominus Ihesus Christus apparuit Sancto Gregorio in tale effugie'; begins: ' Apon a day Saynt Gregore'; ends: '[THORN]en loke [thorn]ou say anon | Dewowtle [thorn]is confession'.
First stop was Sungai Apon where youngsters were building a jungle walkway.
On the first arch there had been 'a trophy of "decollated heads"' under the inscription 'Sequitur Rebelles | Ultor a tergo Deus ("Gods Vengeance Rebels at the Heels pursues")', explained by Ogilby as 'representing in a Trophy the late Example of God's justice apon the Rebels, who committed that most horrid murther upon His Majesties Royal Father of Blessed Memory' (p.
The sentences `A bachelor is an unmarried man' (corresponding to [9] above) and `A cat is an animal' (corresponding to [10] above) can be translated as follows: (15) apon ni okunrin ti ko tii gbeyawo.
For it is reported, that the Camelion cannot take white culler: but Alcibiades could put apon him any manners, customes, or facions, of what nation soever, and could followe, exercise, and counterfeate them when he would as well the good as the bad.