| 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 |
Hi, Our PTT has put in a SMF link between two of our concentrators but have had some problems with the modules themselves, which prompted the following questions; 1) I know the SMF link requires a minimum 12 DB loss, but if the link is installed without this minimum can it damage the receiver and what are the tolerances (ie will -x db simply not work but -y Db actually cause damage) 2) the PTT have also asked what the expected output power of the SMF interface is and what the input thresholds are - can anyone supply this info please? Thanks for any info Steve
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 344.1 | Watch out for high BER | LEVERS::KIRK | tis a gift to be simple | Mon Sep 09 1991 09:36 | 33 |
Hello,
Some quick answers for your questions.
1. Overdriving the receiver probably will not damage it, but there
will be an unacceptably high Bit Error Rate. This will result in the
link being shut down. The minimum 12 dB loss ensures that the
receiver is operating within the acceptable range of input power.
2. The output power of the laser is specified as:
-8.0 dBm to -3.25 dBm
The maximum power output is consistent with Class 1 laser safety
requirements, and thus requires no special treatment. Class 1
laser systems are considered as inherently safe.
The receiver input levels must be within the range of:
-30 dBm to -14 dBm
Attempts to operate SMF FDDI links with received optical power
greater than -14 dBm, or less than -30 dBm will result in high
Bit Error Rates and subsequent shut down of the link.
Regards,
Richard L. Kirk
Networks and Communications
FDDI Optical Technology Group
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| 344.2 | Thanks for the answers | COMICS::WOODWARD | Smile! | Mon Sep 09 1991 10:18 | 0 |