Subject: Pad 1310nm cross-connects? Date: Sat, Oct 19, 2013 at 07:33:19PM -0700 Quoting Chris Costa (ccosta92...@gmail.com): > What are the opinions/views on attenuating short, 1310nm LR cross-connects. > Assume < 20m cable length and utilizing the same vendor optics on each > side of the link. Considering the LR transmit spec doesn't exceed the > receiver's high threshold value do you pad the receiver closer to the > median RX range to avoid potential receiver burnout over time, or just > leave it un-padded?
LR usually needs padding in that scenario, IMHO. This also
applies to MMR interconnects or other "premises" / "campus" situations. 5
or 10dB depending on patching quality -- sometimes up to 15. The value
is best determined by measuring the signal. Then compare the measurement
with the line card / SFP datasheet and determine the amount of padding
necessary. As you write, the damage from overload is gradual, so simply
trusting "it works" is quite bad for longevity reasons.
Not all line cards and / or optical modules report the input signal
level, so a good meter sometimes is necessary.
Get a good level meter, and a reasonably good light source for
testing and calibration purposes. I'm happy with our purchase of
SMLP4-4[0] from AFL Noyes.
--
Måns Nilsson primary/secondary/besserwisser/machina
MN-1334-RIPE +46 705 989668
Pardon me, but do you know what it means to be TRULY ONE with your BOOTH!
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http://www.aflglobal.com/Products/Test-and-Inspection/Loss-Test-sets/SMLP4-4_Single-mode_Multimode_Loss_Test_Kits.aspx
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