[vcf-midatlantic] SX GBIC fiber cable speed

Dave McGuire mcguire at neurotica.com
Tue Feb 16 19:11:09 UTC 2021

On 2/16/21 10:38 AM, Ethan O'Toole via vcf-midatlantic wrote:
>>   When I was working in MD, we had a customer with a long RS-232 run 
>> between buildings. I was there several times to replace the 1488 and 
>> 1489 chips in the remote printer. They never did do anything about it.
> As long as the ICs are in sockets, buy some spares and keep them on hand 
> I guess.

   Yep.  Fortunately 1488s and 1489s are cheap and plentiful.  And truth 
be known, they're actually extremely resilient...Visualize the harsh 
electrical environment of typically dozens to hundreds of feet of wire, 
running past things like blowers, lighting fixtures, etc, then being 
connected directly to an IC pin.  Yes, they die, but only after the most 
egregious of insults.

> Technically ethernet has magnetics, it's isolated. Most likely it's the 
> transformer module that gets blown out. But I have never tried to fix 
> one. The transformers keep the ground loops from happening I'd imagine.

   For "DC" stuff like ground loops, sure, but when a pulse enters a 
transformer, a pulse exits a transformer...and if it's a big pulse, well..


Dave McGuire, AK4HZ
New Kensington, PA

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