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0 pointstenebrisalietum4y ago0 comments

I think this is common in places where they don't expect moisture to reach, but then things change and it gets there anyway.

If your POTS lines are down and the telecom company is telling you a "wet pulp repair" is underway, your phones are going to be down for a while because a bunch of paper-insulated cables need to be manually rewired because they got wet and corroded.

I found this interesting: http://etler.com/docs/bsp-archive/629/629-295-300_I3.pdf - guess it's standard practice to dry out the lines, wrap in cloth, put dessicant and then seal it.

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jcims4y ago

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 that has worked with air compressors knows that pumping ambient pressurized air down into underground pipes is a recipe for condensation, so high capacity air driers are required to remove the water before it goes underground.

Any kind of outage on the compressor or dryer is effectively an emergency because water infiltration can happen almost immediately, creating an outage and extremely expensive repair.

ComputerGuru4y ago

> I know there are some telecom folks on here that may be provoked to correct me

Aka Cunningham’s law

> Any kind of outage on the compressor or dryer

I’m confused: isn’t a bigger concern any physical damage to the conduit anywhere in the run that is too large for the compressor to overcome? Or are we talking football-field-sized compressors here?

BoorishBears4y ago

http://www.airtalk.com/z_ref-4_1.html

Johnythree4y ago

The gas flow on each line was monitored with flow gauges, so any increase could be attended to before it became a problem.

stefan_4y ago

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.

oasisbob4y ago

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.

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Johnythree4y ago

It depends on the country, but originally our Telephone Companies were motivated by Quality of Service. However all that changed when the companies were privatised and profits became their only concern.

Historically there was a continuous upgrade of equipment as the technology improved. Manual exchanges became automatic, step-by-step gave way to cross-bar which gave way to electronic exchanges. Analog phones were replaced with digital and ADSL. And had that steady improvement continued, ADSL would have routinely been replaced with Optical fiber.

What stopped the perpetual upgrades was the arrival Thatcher/Regan/Howard and the advent of Neoliberalism. Which meant that anything which provided a Public Service (gasp Socialism!) was completely abandoned. We are only now starting to realise the long term cost of their vandalism.

jcims4y ago

I would bet this is a capex/opex thing.

djweis4y ago

There is still a lot of it in service. Sometimes you'll see a tank of nitrogen chained to a pole. It is there to put pressure through the cable to keep water out of a cut/nick on the lead sheath. The lines are pressurized normally from the central office and if the monitoring shows a drop in pressure (a cut in the sheath), they roll out cable maintenance.

j / k navigate · click thread line to collapse

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jcims4y ago

Any kind of outage on the compressor or dryer is effectively an emergency because water infiltration can happen almost immediately, creating an outage and extremely expensive repair.

ComputerGuru4y ago

> I know there are some telecom folks on here that may be provoked to correct me

Aka Cunningham’s law

> Any kind of outage on the compressor or dryer

BoorishBears4y ago

http://www.airtalk.com/z_ref-4_1.html

Johnythree4y ago

The gas flow on each line was monitored with flow gauges, so any increase could be attended to before it became a problem.

stefan_4y ago

oasisbob4y ago

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.

2 more replies

Johnythree4y ago

jcims4y ago

I would bet this is a capex/opex thing.

djweis4y ago

j / k navigate · click thread line to collapse