In article , snipped-for-privacy@yahoo.com wrote: :I am using a 1000B-T Copper to 1000B-FX(15kms ) media converter.
Would that be something similar to the Allied Telesyn AT-MC1005/2 ? The installation manuals for that specifically show a pair of them being used in series, but I see no information at all about latency or propagation delay in them. Nothing in the FibroLan GSM1012 literature either. The Fiberdyne FTX-210M page specifically says "with no performance degradation"
:What would be the propgation delay introduced due to the medium of :Fiber( 300m per microsecond) and due to the medium of Copper ?
Interesting. I found one site offering a specific cat5e cable that indicates that the propagation delay is
534 + 36/sqroot(f) ns/100m maximum
where f is the frequency in MHz from .772 to 100.
I see other sites saying 4.7 ns/m to 5.2 ns/m -- it appears that doesn't take into account the connectors or whatever other fixed factor is at work.
If I read the sites correctly, ~540 ns is a common fixed-delay figure independant of cable length, and that one must then add the 4.7-ish ns/m for distance. That's like saying that each 100 m copper patch cable has a propagation delay equivilent of about 210 m worth of wire.
So, how many can you cascade without affecting the propagation delay? None! The convertors are useless without a copper patch cable to connect them to something (if only another convertor), and that cable is going to have a big delay no matter how short it is.
Note: I have little experience in the physics of cables. I am
*not* an expert in this area: I'm just good at google'ing and interpreting what I find there.