[c-nsp] Attenuate me...

[Majdi Abbas]

On Thu, Dec 22, 2005 at 07:58:28AM -0500, Robert E.Seastrom wrote:
> I've got a couple of e0 OC12 IR POS cards in routers in adjacent racks
> (don't laugh, they were cheap!) talking to each other over a 4m long
> chunk of SM fiber.  Getting errors out the wazoo.  At a guess, I'm
> probably overdriving the receiver.
> 
> Can anyone suggest an appropriate value for attenuators for this kind
> of configuration?  Docs I've seen suggest that this should work, but
> barely, with no attenuators...  what do people find works in practice?
> 6 dB?  10 dB?

	Since these are IR cards at 1310, I'd suggest trying a 3db pad
first.  2 should work, but might be pushing it a bit.  Start with 3 and
if that isn't enough, go to 5.

	These cards launch far enough down that 10 dB might work but
would put you pretty far down the receive window.  15 is right out.

	Oh, and Merry Christmas.

	--msa