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What leads to that design? I mean, why are they going to such expense to keep wire separated? Was insulation prohibitive? Had twisted pairs not been invented ye
by jws 13y ago
What leads to that design? I mean, why are they going to such expense to keep wire separated? Was insulation prohibitive? Had twisted pairs not been invented yet, making crosstalk too severe on closely bundled wires?
- BuildTheRobots 13y agoI don't believe they are trying to keep every cable separated. I think on the top photo we're looking at bundles of cables -like a nicely done server room, different bundles go to different places hence the arrangement.
- gpvos 13y agoTwisted pair was invented shortly after the telephone line, see https://en.wikipedia.org/wiki/Twisted_pair#History https://en.wikipedia.org/wiki/Twisted_pair#History and the image there: the wires were still separated by distance. At least in Europe, however, many places still used single-wire connections with return through earth for local lines during the first few decades. Not sure about Stockholm. Anyway, I am guessing insulation was too expensive.
- chronomex 13y agoThat was before high-quality wire insulation was invented. Each subscriber's telephone line had to be physically separate from all the others, because they weren't coated in anything. http://scienceray.com/technology/information/open-wire-telephone-lines/ http://scienceray.com/technology/information/open-wire-telep...
- darkmighty 13y agoI guess the great shift were low cost polymers for insulation. In the early 20th century rubber was very expensive, extracted from trees (in a process much like maple syroup extraction I guess). http://en.wikipedia.org/wiki/File:Latex-production.jpg http://en.wikipedia.org/wiki/File:Latex-production.jpg
- chronomex 13y agoActually before that came paper insulated cable: http://www3.alcatel-lucent.com/bstj/vol12-1933/articles/bstj12-1-1.pdf http://www3.alcatel-lucent.com/bstj/vol12-1933/articles/bstj... These cables had paper pulp insulation around the wires, and a jacket of soft lead around the whole cable. The cable is pressurized with dry air at the central office to drive out water, though flooded lines can still be a problem sometimes. If you see any dirty-light-grey aerial cable (usually 2-5 cm diameter) in a city, that's probably pulp-insulated lead cable still in service.
- Aardwolf 13y agoSo that's how Nokia, the rubber company, started in the telephone cable business! Anyway, the tower looks awesome, like 19th century science fiction...
- mcguire 13y agoWithout any real knowledge (this is the Internet, after all), I'm going to go with a combination of uninsulated and no twisted pairs (see http://en.wikipedia.org/wiki/Twisted_pair#History http://en.wikipedia.org/wiki/Twisted_pair#History) plus the rapid expansion of the system precluding any real planning. ("Around 1893, the country leading the world in telephones per 100 persons (teledensity) was Sweden with 0.55 in the whole country but 4 in Stockholm (10,000 out of a total of 27,658 subscribers). This compares with 0.4 in USA for that year.", see http://en.wikipedia.org/wiki/History_of_the_telephone#Early_commercial_instruments. http://en.wikipedia.org/wiki/History_of_the_telephone#Early_...)