100baseFX & DM9161

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Has anyone used the DM9161 in 100base FX mode ?

I am managing to get a link - but no data transfer.

I use the 3 OPT pins to set the mode (010 - 100baseFX) - and I can confirm
that bit 10 of register 16 is 0.

I am a newbie to fibre - are there any other common-sense tips that I should
know ? Maybe things like bend radius of the fibre ??

I am using the HFBR5803 from Agilent.


Re: 100baseFX & DM9161
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From a consumer's persective on 100FX...

a) Today, fiber is pretty tolerant of abuse.  It's not the fragile stuff
it used to be.

b) Fibers are rated on their diameter, their wavelengths, and their
mode.  Wavelengths are rarely referenced, since fibers within each
general-purpose class have similar properties.

You probably need to be using *multi-mode* fiber with a 62.5/125
micrometer core/cladding (this is "consumer grade" fiber, e.g. for lower
speed or short-haul [<2km] use).  A newer 50um multimode is available;
you would see some signal loss if you mis-matched the types, but not
fatal in most cases.  The specs should be printed on the fiber cable.

You would most likely *not* want *single mode* fiber (commonly ~12.5um,
IIRC, and used for long distances).  General-purpose LAN transceivers
will not work with single-mode fiber.  (OTOH, single-mode transceivers
will work properly over multimode fiber for short distances, in a

c) you may find that link is not a 2-way state.  If one strand is bad,
you may get link in only one direction.

d) Getting very basic... did you crossover the jumper cable (connect TX
to the peer's RX)?

Good luck!

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