[Gb-ccb] Information and advice on optic-fibre ethernet

[John Ford]

Martin Shepherd writes:
 > Regarding the optic fibre ethernet at Green Bank. Is this 10BaseFL or
 > 100BaseFX? Also, am I correct in recalling that in both of these
 > cases, multi-mode fibers are used, and that the fibres have ST style
 > connectors at each end?

We use both.  I would say to use the 100FX.  The connectors are ST for
100FX and 1GB links.

 > 
 > I would also be interested to hear which UTP <-> optic-fiber media
 > converters you tend to use, and recommend, since there will have to be
 > one of these in the CCB case. I will need one that can be powered from
 > DC. 

We use the allied-telesyn FS-202, which is a smart converter (a
switch, really) that can handle 10 or 100 Mb twisted pairs.  It is a
3" square box about 1" tall.  It uses a 12 volt power supply

 > Note that I plan to use metal fiber-optic bulkhead couplers to
 > pass the TX and RX fibers through the wall of the CCB chassis.

For best RFI shielding, you should consider using a waveguide beyond
cutoff farrangement to get the fibers into the system.  If you are
sure your metal connectors will work, then that would be fine, too.

On the subject of RFi shielding, have you a block diagram of the
system and the interconnections between assemblies that we could look
at to pick out any RFI problems?

John