| Title: | FDDI - The Next Generation | 
| Moderator: | NETCAD::STEFANI | 
| Created: | Thu Apr 27 1989 | 
| Last Modified: | Thu Jun 05 1997 | 
| Last Successful Update: | Fri Jun 06 1997 | 
| Number of topics: | 2259 | 
| Total number of notes: | 8590 | 
I have a customer that has some installed fiber that accepts two signals; one at 1300nm and the other at 850nm. The 1300nm wavelength is already being used. Is it possible for our FDDI signal, via some external adapter/converter to use 850nm? If it is possible, then I would assume budgets/distance/etc would be impacted. It's likely to be a 'temporary' solution to avoid pulling new fiber under roads, parking lots, rail spurs, and/or runways. Thanks, -John
| T.R | Title | User | Personal Name | Date | Lines | 
|---|---|---|---|---|---|
| 504.1 | KONING::KONING | Paul Koning, NI1D | Tue Mar 17 1992 22:24 | 15 | |
|     I don't know of any devices that do this.  Certainly there is no 850 nm
    hardware I know of suitable for FDDI rates, and the fiber would only
    support very limited distances in any case.  Finally, it sounds like
    you're talking about "dual window" fiber, which is specified for either
    wavelength -- but that doesn't mean you can easily run both together
    over the same fiber.  Apart from all the above issues, you'd need some
    sort of optical combiner at one end and splitter/filter at the other
    end.  Again, these are things that are possible in principle, but
    that's not to say you can do it in practice.
    
    This sort of thing is why we recommend pulling fiber in fair sized
    cables, not just one or two at a time.  The only sensible solution is
    to pull new fiber -- and enough of it this time.
    
    	paul
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| 504.2 | Dual Frequency FDDI - T&N EIC | WARP5::MCCLOUD | Dennis McCloud - SOA ANC | Thu Apr 02 1992 15:45 | 7 | 
|     John,
    
    I seem to remember a special implementation by the T&N EIC last year
    where they utilized Wave Division Multiplexers and a modified
    DECconcentrator at 1550 nm and 1300 nm to have two FDDI LANs over the
    same fiber.  I don't know if the group still exists but the contact
    was Mike Martin @MKO or TNEIC CUSTOM @MKO or SOLVIT::TNEIC.
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