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ADSL works over wet string (2017)

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Re: ADSL works over wet string (2017)

#81

Post by SV_BubbleTime »

NovemberWhiskey wrote: post #34
VHRanger wrote: post #12

Earlier quoted context omitted.

That's not exactly correct. Electrons don't flow through wires - there's a one-way flow of the ambient electrons around the wire from the field created. See here: https://www.youtube.com/watch?v=bHIhgxav9LY

You're confusing the electrons and the electromagnetic fields. The electrons absolutely do migrate through the wires; the electric field does not. P.S. that video appears to have been written to confuse/generate controversy and does a terrible job of actually explaining.

> The electrons absolutely do migrate through the wires;

That’s true. But very slowly in electrical terms. If I remember right the actual electronics in a reasonable circuit I read about was something like 1” per second. The vast majority of work done is an electron shuffle of bouncing into the next one in space.

Re: ADSL works over wet string (2017)

#82

Post by throw0101a »

toast0 wrote: post #78
throw0101a wrote: post #69

Earlier quoted context omitted.

There are IEEE standards for single-pair Ethernet: > In addition to the more computer-oriented two and four-pair variants, the 10BASE-T1,[17] 100BASE-T1[18] and 1000BASE-T1[19] single-pair Ethernet physical layers are intended for industrial and automotive applications[20] or as optional data channels in other interconnect applications.[21] The single pair operates at full duplex and has a maximum reach of 15 m or 49…

Sadly, there's not much in the way of equipment for this. I could really use two small 10BaseT-1 to 10BaseT converters, preferably both powered from one end.

Seems to be mostly in the automative and industrial space, with some embedded stuff.

I could also see it being useful for door security (badge readers, latch control).

Re: ADSL works over wet string (2017)

#83

Post by Terry_Roll »

giardini wrote: post #23

ADSL, being essentially a form of alternating current, will pass through an air gap. I was enlightened on this by an AT&T tech who pointed out that one of my ADSL lines had several breaks and could not carry DC but the ADSL signal still came through. The other line was dead so I was running essentially on one wire with an earth ground. Here is an interesting discussion: "Phone line with 1 broken wire still gets ADSL2…

Its DC. If you had to imagine it, think of it as a range of radio stations being broadcast down a wire instead of over the air and your router can tune in to all the radio stations at the same time and then piece together the different bits of data being broadcast. Long Wave would be ADSL, ADSL2, Medium Wave ADSL2+, and FM would be higher forms of ADSL to give you your 40Mb, 80Mb, 100Mb download speeds.

With this broadcasting of signals down a wire now known, it becomes somewhat unsurprising anything capable of transmitting an electrical voltage & current would be capable of transmitting ADSL. Not knocking their effort though, Arnold and Arnold have always like to demonstrate their knowledge. One of them has a personal blog which can be quite interesting.

I wonder if they have considered trying to adapt an SDR dongle to become an ADSL transmitter?

Re: ADSL works over wet string (2017)

#84

Post by NovemberWhiskey »

SV_BubbleTime wrote: post #81
NovemberWhiskey wrote: post #34

Earlier quoted context omitted.

You're confusing the electrons and the electromagnetic fields. The electrons absolutely do migrate through the wires; the electric field does not. P.S. that video appears to have been written to confuse/generate controversy and does a terrible job of actually explaining.

> The electrons absolutely do migrate through the wires; That’s true. But very slowly in electrical terms. If I remember right the actual electronics in a reasonable circuit I read about was something like 1” per second. The vast majority of work done is an electron shuffle of bouncing into the next one in space.

When you say "work", what do you mean? I get the impression you're talking about a model like there's a long tube full of ball-bearings and when you push one in, one drops out the other end?

That model isn't right; think about a transformer - energy is transferred between conductors that are not physically connected at all.

Re: ADSL works over wet string (2017)

#85

Post by toast0 »

throw0101a wrote: post #82
toast0 wrote: post #78

Earlier quoted context omitted.

Sadly, there's not much in the way of equipment for this. I could really use two small 10BaseT-1 to 10BaseT converters, preferably both powered from one end.

Seems to be mostly in the automative and industrial space, with some embedded stuff. I could also see it being useful for door security (badge readers, latch control).

For me, I've got a gate with a keypad. It's got an ethernet port, but they only ran 3 pair to it, and it works best with 2 pair for voice communications, so I've only got one pair for data, not enough to use.

Re: ADSL works over wet string (2017)

#86

Post by hereforphone »

Terry_Roll wrote: post #83
giardini wrote: post #23

ADSL, being essentially a form of alternating current, will pass through an air gap. I was enlightened on this by an AT&T tech who pointed out that one of my ADSL lines had several breaks and could not carry DC but the ADSL signal still came through. The other line was dead so I was running essentially on one wire with an earth ground. Here is an interesting discussion: "Phone line with 1 broken wire still gets ADSL2…

Its DC. If you had to imagine it, think of it as a range of radio stations being broadcast down a wire instead of over the air and your router can tune in to all the radio stations at the same time and then piece together the different bits of data being broadcast. Long Wave would be ADSL, ADSL2, Medium Wave ADSL2+, and FM would be higher forms of ADSL to give you your 40Mb, 80Mb, 100Mb download speeds. With this bro…

What's DC? "Radio stations" communicate via alternating quantities (EM waves)

Re: ADSL works over wet string (2017)

#87

Post by unixhero »

DaiPlusPlus wrote: post #45
giardini wrote: post #23

ADSL, being essentially a form of alternating current, will pass through an air gap. I was enlightened on this by an AT&T tech who pointed out that one of my ADSL lines had several breaks and could not carry DC but the ADSL signal still came through. The other line was dead so I was running essentially on one wire with an earth ground. Here is an interesting discussion: "Phone line with 1 broken wire still gets ADSL2…

> Anyway, my hat is off to the people who designed and implemented ADSL. It's a blessing-and-a-curse: too many incumbent ISPs in highly-developed nations used ADSL's ability to run on anything as an excuse to put-off FTTH deployments (looking at you, BT).

Telenor

They also did the same, stalling and delaying, insisting on introducing ISDN 64/128kbit instead of going straight to DSL like Holland did.

Re: ADSL works over wet string (2017)

#88

Post by Dylan16807 »

nabla9 wrote: post #29

Most HDMI and Coaxial cables are little more than wet string https://ec.europa.eu/docsroom/documents/46433 >only 10% of the HDMI RMCD met an acceptable EMC quality of at least 50 dB coupling attenuation

RMCD sure is an awkward way of spelling "cable". Especially when nobody else seems to use this acronym?

Re: ADSL works over wet string (2017)

#89

Post by oasisbob »

stefan_ wrote: post #77
jcims wrote: post #30

Earlier quoted context omitted.

I know there are some telecom folks on here that may be provoked to correct me but pulp was standard before the advent of cheap plastic insulation in the 1950s on up. I live in the midwest and my brother is a lineman for AT&T. There is an astonishing amount of pulp-insulated phone line still in service today. In order to keep it dry, the conduit that the pulp lines are run through is pressurized to 5-10psi. Anyone th…

The more you learn about this ancient cable technology the more absurd it becomes. We shower these fuckers with money but they would rather keep their paper insulated phone lines with permanent compressors and dryer running than braindead simple fiber. No wonder it is permanently broken and they can't keep a single 9 of reliability.

Fiber may be simple, but the way we use it is not. Unlike copper, a GPON fiber install is going to have active electronics and splice trays for every several dozen subscribers.

Plenty of opportunities for water ingress to still cause problems.

Re: ADSL works over wet string (2017)

#90

Post by martinald »

samwillis wrote: post #61
DaiPlusPlus wrote: post #45

Earlier quoted context omitted.

> Anyway, my hat is off to the people who designed and implemented ADSL. It's a blessing-and-a-curse: too many incumbent ISPs in highly-developed nations used ADSL's ability to run on anything as an excuse to put-off FTTH deployments (looking at you, BT).

I think we (in Stamford Lincolnshire, UK) must be pretty unique right now with TWO competing FTTP startups both rolling out on the same streets. One day you will see Lightspeed Broadband pulling their fibre through the BT ducts and putting boxes on the top of telegraph polls. The next day Upp Brordband will be on the same street. So bizarre they they are doing the same town! Apparently we are due to have BT put in th…

Basically there is an enormous amount of capital (at least £10bn from startup providers) out there going into UK FTTH builds. BT focussed too much of content (BT Sport) instead of FTTH and private equity now thinks there is an opp to steal marketshare from BT/VM.

However BT have now now committed £10-20bn, VM probably a few billion.

It will quickly consolidate like it always does.

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