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Re: [802.3ae_Serial] Cable plant values?





Tom:

Legacy 62.5 um fiber attenuation was specified as 3.75 dB/km at 850 nm as
defined in TIA-568 Rev A.   TIA-568 has recently been updated (2001) as
Rev. B that modified the 850 nm attenuation to 3.5 dB/km for 62.5 um fiber.
Also, TIA-568 Rev B now includes 50 um multimode fiber with an attenuation
of 3.5 dB/km at 850 nm.

Hope this helps.

Doug



                                                                                                                                             
                    "Lindsay, Tom"                                                                                                           
                    <tlindsay@stratoslightwave.com>                To:     "802.3ae Serial reflector (E-mail)"                               
                    Sent by:                                        <stds-802-3-hssg-serialpmd@ieee.org>                                     
                    owner-stds-802-3-hssg-serialpmd@majordom       cc:     "Doug Coleman (E-mail)" <doug.coleman@corning.com>                
                    o.ieee.org                                     Subject:     [802.3ae_Serial] Cable plant values?                         
                                                                                                                                             
                                                                                                                                             
                    05/17/02 12:07 PM                                                                                                        
                                                                                                                                             
                                                                                                                                             





Questions

1. Table 52-25  quotes 3.5 dB/km max attenuation at 850nm, whereas the
spreadsheet uses 3.75.  10GFC also quotes 3.75 in its documentation. Which
value is correct?  ll 3  sources agree on 3.5 dB for 50 micron fiber.

2.  Table 52-24  shows channel insertion losses. Can someone explain where
the values come from  for the 850 nm variants? Except for 2000 MHz-km, I
get significantly  different values. The values in the table are not
consistent with the model nor  with the budget tables for the PMDs.

Thanks,  Tom
Stratos NW
(425) 672-8035  x105

(See attached file: Tom Lindsay @ work.vcf)

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