I think it's always been a differential distance, not a maximum
distance. I think a lot of people just misinterpret it.
------------------------------------------------------------------------
*From:* AF <[email protected]> on behalf of Chuck <[email protected]>
*Sent:* Tuesday, August 19, 2025 4:55 PM
*To:* [email protected] <[email protected]>
*Cc:* [email protected] <[email protected]>
*Subject:* Re: [AFMUG] how is underground FTTH done?
There was in the beginning due to the timing and cuing of ONT upstream.
It was to ensure 32 ONTs could all be transmitting max traffic at the
same time. That is what Calix told me many years ago.
Sent from my iPhone
On Aug 19, 2025, at 11:50 AM, Josh Luthman
<[email protected]> wrote:
From what I've read, the issue was the timing between the farthest
& closest ONT. There was no 20km timing limitation from OLT to
anything.
On Tue, Aug 19, 2025 at 12:39 PM <[email protected] <mailto:chuck@go-
mtc.com>> wrote:
Original GPON specs had a timing limitation of 20 km.
*From:* AF <[email protected] <mailto:af-
[email protected]>> *On Behalf Of *Josh Luthman
*Sent:* Tuesday, August 19, 2025 6:31 AM
*To:* AnimalFarm Microwave Users Group <[email protected]
<mailto:[email protected]>>
*Subject:* Re: [AFMUG] how is underground FTTH done?
Class C optics are rated for 60km or 42mi. That's a hell of a
distance when you're only doing 1:32. We did 1:2 and 1:32 on
the sixteenth PON port until we built more to justify another OLT.
On Mon, Aug 18, 2025 at 6:13 PM Chuck McCown <[email protected]
<mailto:[email protected]>> wrote:
When you work out a 32:1 GPON, the timing distance
limitations are exhausted before you run out of light.
Splits are a 3 dB loss. A good splice will be .02dB. So
don’t worry about splices.
*From:* AF [mailto:[email protected] <mailto:af-
[email protected]>] *On Behalf Of *Dev
*Sent:* Monday, August 18, 2025 9:56 AM
*To:* AnimalFarm Microwave Users Group <[email protected]
<mailto:[email protected]>>
*Subject:* Re: [AFMUG] how is underground FTTH done?
The thing with PON is that every time the light hits a
splitter it loses a bit of strength, so you sort of have to
plan to use a little hotter SFP in your OLT sometimes.
Luckily, those are getting way cheaper nowadays, so it’s not
the end of the world, but you do have to plan for that.
Plus, each splice you do cuts down the signal a bit more.
Fusion splicers only lose a tiny bit, but a physical
connector can lose a bunch more, like the equivalent of a
mile or more of distance, and a piece of crud on an
uncleaned connector can lose 5 miles distance, so make sure
you clean them with those cheap cleaner tools.
On Aug 18, 2025, at 8:39 AM, Josh Luthman
<[email protected]
<mailto:[email protected]>> wrote:
Splitters are waaay small. Smaller than a standard
house key.
What you are looking at is an MST terminal, looks like 8
ports. There can be a splitter inside of that yes. You
can have the MST with 8 fibers splice to another 8
fibers or you can have what is in your picture have 1
fiber in, split 1x8, and then have 8 ports out for the
installers to simply plug in to.
If that MST is a 1x8, you can have a 1x4 before it,
between the MST and OLT. That makes for OLT -> 1x4
splitter -> 1x8 splitter/MST. That is still a 1x32 split.
On Mon, Aug 18, 2025 at 11:34 AM Ken Hohhof
<[email protected] <mailto:[email protected]>> wrote:
I thought PON used like 16:1 or 32:1 splitters, and
in this photo, I assumed that’s what the black boxes
were.
*From:* AF <[email protected] <mailto:af-
[email protected]>> *On Behalf Of *Josh Luthman
*Sent:* Monday, August 18, 2025 10:16 AM
*To:* AnimalFarm Microwave Users Group
<[email protected] <mailto:[email protected]>>
*Subject:* Re: [AFMUG] how is underground FTTH done?
Don't assume that about aerial. That's not how it
works. Don't think about it in terms of taps.
Generally speaking, installations are PON. What we
do is design the fiber so we can hook up 100% of
homes. We assign a color to every house.
The first thing to think about is that you have to
access the individual strand out of the cable, be it
12/24/48/144/etc. That is done with a SpliceCase or
you splice on an MST for an ez mode plug. At
Imagine we only splice - no connectors, no MST, no
plugs, etc.
Second thing is that when there's a cable up and
down the road, you just need access to it through
the case/MST from the house. This can be from the
house to the handhole (concrete box in the ground)
or you can run it from the house to the handhole
through some 1.25" duct to the next handhole where
there is one case.
I can show you what it looks like if you don't get
it yet.
On Mon, Aug 18, 2025 at 11:11 AM Ken Hohhof
<[email protected] <mailto:[email protected]>> wrote:
The fiber train left without me, so maybe
someone here can help me understand how the
physical installation is typically done.
I’ve seen aerial fiber and it’s pretty
straightforward, I see splitters up on poles
maybe at each intersection, and to hook up a
customer, they run a drop wire from the nearest
splitter to the house. If take rate is better
than expected or a new house is built, worst
case I assume they just add a splitter.
But I also see FTTH deployments going in where
they are boring for duct in the ROW and putting
a little handhole in front of every house. How
does this work? Are they using taps instead of
splitters? If not, when they get a customer
install order, do they pull his drop cable
through all the handholes to a splitter? That
doesn’t seem feasible. Are they dedicating a
strand to each house and pulling the main cable
out each time and splicing to that strand? And
what if they estimate the take rate wrong, or a
new house is built?
There’s probably a simple explanation and once
someone enlightens me it will be a Duh! moment.
--
AF mailing list
[email protected] <mailto:[email protected]>
http://af.afmug.com/mailman/listinfo/
af_af.afmug.com <http://af.afmug.com/mailman/
listinfo/af_af.afmug.com>
--
AF mailing list
[email protected] <mailto:[email protected]>
http://af.afmug.com/mailman/listinfo/af_af.afmug.com
<http://af.afmug.com/mailman/listinfo/af_af.afmug.com>
--
AF mailing list
[email protected] <mailto:[email protected]>
http://af.afmug.com/mailman/listinfo/af_af.afmug.com
<http://af.afmug.com/mailman/listinfo/af_af.afmug.com>
--
AF mailing list
[email protected] <mailto:[email protected]>
http://af.afmug.com/mailman/listinfo/af_af.afmug.com
<http://af.afmug.com/mailman/listinfo/af_af.afmug.com>
--
AF mailing list
[email protected] <mailto:[email protected]>
http://af.afmug.com/mailman/listinfo/af_af.afmug.com <http://
af.afmug.com/mailman/listinfo/af_af.afmug.com>
--
AF mailing list
[email protected]
http://af.afmug.com/mailman/listinfo/af_af.afmug.com
