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Re: ATM over Multimode/single mode fibre

  • From: vhalkka@cc.helsinki.fi
  • Date: 14 Dec 1996 00:40:49 +0200

In article <ndowney.76.32AFDDF7@net-cs.ucd.ie>,
Niall Downey <ndowney@NET-CS.ucd.ie> wrote:

>I have heard about an active device, for about $1500, which will allow a 
>proper multimode to single mode interface.
>
>Any information would be very welcome as I am having sleepless nights worrying 
>about wether this will work.

You must try it. It will probably work with both interfaces.

The greatest problem with singlemode is the power.. a run that's too
long for multimode fiber can be too short for a singlemode. We have to use
attenuators at some places, but I believe your multimode is bad enough ;-)

If you have power budget problems it can be seen from the sonet
counters:

sonet Port 1A1 Counter              Value           Delta
------------------------------  --------------  --------------
sonetSectionBIPs                    4165160289               0
sonetSectionLOSs                         86777               0
sonetSectionLOFs                         86777               0
sonetLineBIPs                                0               0
sonetLineFEBEs                               0               0
sonetLineAISs                            86777               0
sonetLineFERFs                               0               0
sonetPathBIPs                                0               0
sonetPathFEBEs                               0               0
sonetPathLOPs                                0               0
sonetPathAISs                            86777               0
sonetPathYellows                         86777               0
sonetAtmCorrectableHCSs                      0               0
sonetAtmUncorrectableHCSs                    0               0

If you have a reason to believe that you have too much power loosen
the connector ( but keep the lights dark/green) and read sonet counters.

You should be able to find a position where it works. (Delta should be
0) 

Then go and buy an attenuator or two.

If you connect a singlemode/multimode converter (why, you have both
already) to the fore SM port the fibers will be very short and it is almost
sure that you also need attenuators.

VesA