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10mbps over 1km on a single pair of wires

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Re: 10mbps over 1km on a single pair of wires

#141

Post by Aloha »

geozimm wrote: post #84

All these things are related. Back in the 1990s I worked with others to develop DSL technologies (ADSL, HDSL, VDSL) for telcos. Why not fiber, some ask? oh, fiber materials may be sand, but installed fiber is sand, energy, and labor. Installation costs trump everything - use what you have for the physical medium. While we (PairGain) also made point-to-point private links, it was clear then, and even moreso now that m…

I remember seeing your guys HDSL hardware in the field what seems like a million years ago. (for those without a telecom background) It was pretty common as a way to extend T1's without conditioned lines or repeaters then.

Interestingly enough, I'd done direct t-spans's inside of a building over house cable in a situation that was too long (and too poor of cable) to do Ethernet.

Re: 10mbps over 1km on a single pair of wires

#142

Post by Aloha »

DannyBee wrote: post #48
silviot wrote: post #21

Earlier quoted context omitted.

What's the difference in price between 1km of fiber vs 1km or single pair wire? It might play a role in this solution being cheaper than immediately apparent.

The fiber is much cheaper because it's so much more common. For example: I/O fiber is about 0.10 cents a foot or less for 2 fiber cable. (12 fiber is only 20 cents a foot). OSP gel-filled direct burial is 0.55 cents a foot or less for 2 fiber cable. (12 fiber is only 65 cents). This is micro-armored OSP cable, resistant to chewing/damage as well. Basic 18 awg single pair shielded direct burial wire is about 0.80 cent…

When everyone prices fiber, they fail to include the termination costs.

How much are the termination costs on that fiber, per run?

Also, you'd never install single pair direct burial, and almost never shielded (unless its audio and not phone type) - it'd be 4/6/12 pair direct bury gel-filled cable.

Re: 10mbps over 1km on a single pair of wires

#144

Post by Aloha »

yosheli123 wrote: post #2

So I built a tiny single pair Ethernet bridge (10BASE-T1L) that can transmit 10mbps over a kilometer on a single pair of twisted copper wires. Would love to get some feedback for the next iteration

What are the limits on cable characteristics? Capacitance, foreign voltage, etc?

Re: 10mbps over 1km on a single pair of wires

#145

Post by Ahwd »

SPE looks really interesting for CAN/RS485 replacement.

I just noticed Analog devices also has chips finally available even at resellers: ADIN1100 for pure phy like the TI part in this but more interesting once are ADIN1110 (spi bus to MAC+PHY so any mcu with spi bus can communicate with ethernet) and especially ADIN2111 which is 2xSPE PHY + MAC + spi bus so with single chip you can make daisy-chain devices talking at 10base-t1l and the ADIN2111 has simplified rx/tx interface so with small transformer nice galvanically seperated link can be made.

Until now I have used isolated CAN transceivers for links between devices that need ~100m distance as quite many MCU have built-in CAN peripherals but ethernet MAC is usually restricted to the bigger series. The spi bus on the ADIN (and probably later some other chips similar to the ENCJ from microchip) opens this up to smaller lower end devices.

I am really excited for the coming years as I have been waiting for these 10base-T1L devices to be available for roughly two years and the chip shortage in general has not made things easier.

Re: 10mbps over 1km on a single pair of wires

#146

Post by yosheli123 »

0xfaded wrote: post #77
transistor-man wrote: post #75

Awesome project! This would be fairly great fit for underwater UAV's, or like security camera way out on the edge of property. May be a good idea to post on ardu-sub related discussion forums. I'm not aware of an off the shelf module that's point to point ADSL, almost every modem is intended to yell at a ADSL / ADSL2+ host. Did you run into any issues with consumer-grade gigabit switches negotiating 10Mbit?

Blue Robotics sells the fathomX exactly for this purpose. I wouldn't be surprised if it uses the same chip set. https://bluerobotics.com/store/comm-control-power/tether-int...

That tops out at around 300meters. Ours goes beyond 1km. Still there's is awesome for camera feeds; I love the Blue Robotics hardware, SPEBlox Long is just a different application (more industrial automation focussed)

Re: 10mbps over 1km on a single pair of wires

#147

Post by GreyStache »

Aloha wrote: post #138
repiret wrote: post #135

Earlier quoted context omitted.

Last summer the local cable company replaced all their cables in town in order to begin offering digital cable and internet service. I was flabbergasted that they they spent all that money on linemen but still ran coax rather than fiber. As far as I can tell talking to their linemen, its not even FTTN, just FTT-central-office. Assuming its not run by morons, which I'll accept is a bit of a stretch for a cable company…

Cost and Fragility. You can push around 1GHz of bandwidth on the normal hardline-feed line with taps system cable uses, each node is designed to pass by a certain number of households. Coax is.. cheap, forgiving, easy to terminate, and inexpensive to replace - Fiber is more expensive, unforgiving, and much harder to terminate.

Regarding the termination: our local fiber provider handles the termination with some optical precision connector (forgot the name). Both to the sunken-in-sidewalk multiplexer and in the home to the optical termination point (both gpon). So for mass deployments fiber connections do not require fibre welds are not required.

I have to see it play out in practice and I'm not a fan of the idea that one telco controls controls (ie stifles competition) in a gpon scenario. The conduit has recently been placed in our street, so "soon"...

Re: 10mbps over 1km on a single pair of wires

#148

Post by kevin_thibedeau »

upofadown wrote: post #98
midasuni wrote: post #89

Earlier quoted context omitted.

The biggest problem is lightning strikes hitting the cable. The phase wouldn’t matter - and even different earthing wouldn’t matter as long as you only connect any shield at one end. But fibre is so much more versatile if you’re running new cables (unless you want to run power)

... also lightning strikes hitting the ground somewhere in the area. That can induce large voltage differences between the power grounds on the buildings. The voltage difference might be large enough to arc across any isolation provided by the physical network implementation.

My neighbor's house was hit by lightning last year and it took out the ethernet ports on two of my devices. Nothing else was affected though. Those devices still work. They're on a PoE switch (though not using PoE) so that may have been part of the cause.

Re: 10mbps over 1km on a single pair of wires

#149

Post by throwaway____10 »

geozimm wrote: post #84

All these things are related. Back in the 1990s I worked with others to develop DSL technologies (ADSL, HDSL, VDSL) for telcos. Why not fiber, some ask? oh, fiber materials may be sand, but installed fiber is sand, energy, and labor. Installation costs trump everything - use what you have for the physical medium. While we (PairGain) also made point-to-point private links, it was clear then, and even moreso now that m…

What a blast from the past, DSL was an exciting technology.

I did the config and networking of DSLAMs for the first private test installs of Paradyne (Hotwire) DSL hardware in a western state around ~1998-1999, a couple years before DSL really hit the mainstream.

The telecos were slow to move on the technology and didn't do their own centralized rollouts until several years later. We took full advantage of that lead time time to win away a lot of ISDN customers with much lower prices and much faster service. We also saw end of that advantage coming and got out of the business before we had to compete directly with the telecos who could operate at scale and do bundled pricing of the line + service that was harder to compete with. At the time high speed internet over cable was also a while off for the general public.

We also had a tip from a teleco employee that we could use DC Signalling channels / dry copper pairs instead of regular phone circuits (no dial tone, they were meant for alarm service). They cost about 1/2 to 1/3 of the price.

At one point we petitioned to get the local telco to dig up the sidewalk and install several hundred more copper pairs into the building.

It was really interesting to watch the internet access landscape change so quickly.

Re: 10mbps over 1km on a single pair of wires

#150

Post by Aloha »

GreyStache wrote: post #147
Aloha wrote: post #138

Earlier quoted context omitted.

Cost and Fragility. You can push around 1GHz of bandwidth on the normal hardline-feed line with taps system cable uses, each node is designed to pass by a certain number of households. Coax is.. cheap, forgiving, easy to terminate, and inexpensive to replace - Fiber is more expensive, unforgiving, and much harder to terminate.

Regarding the termination: our local fiber provider handles the termination with some optical precision connector (forgot the name). Both to the sunken-in-sidewalk multiplexer and in the home to the optical termination point (both gpon). So for mass deployments fiber connections do not require fibre welds are not required. I have to see it play out in practice and I'm not a fan of the idea that one telco controls con…

I'm still a fan for cost reasons of FTTN, because I think with Coax in the last mile, you can deliver fantastic performance, so long as you're not also trying to delivery video too.

Furthermore if you actually run Coax in duct for buried circuits, its easy to replace with fiber later.

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