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28

10BASE-T saw first light as StarLAN that made use of the already existing twisted-pair category 3 telephone cabling (instead of the dedicated coax that 10BASE5/2 required). That cabling standard carries four pairs to each wall jack. StarLAN (10) and subsequently 10BASE-T had no use for more than two pairs, so they ignored the other two. 100BASE-TX borrowed ...


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What you're looking for is a cable tester able to certify a cable with the entire test suite. The tests must include crosstalk and detailed frequency measurement. Basically, there are three classes of testers: just continuity and shorts - 5-100 € additionally wire map (proper pairings), overall length, possibly rough frequency response (cable class) - 200-...


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To answer the part of your question "Were there some cables that only had two pairs?": I worked at a very large multi-building site that had 8wire/4pr twisted pair in the walls terminating with and split between two RJ13* jacks at each wallplate. (2 pairs going to each) One RJ13 was used for POTS phone, and the other was later used for 10baseT (...


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There's nothing to stop a new twisted-pair standard using a new connector in the design, with more wires. If a physical site had to choose between using existing 8-wire / 4-pair and recabling everything to use a new standard, then the additional costs would push most sites to stay with existing wiring for as long as it fills the need. One half-way point ...


1

we also see that the fiber is only used till the networking device and not the client nodes like PC or laptop. That isn't really true. Technically, running fiber to the desktop isn't a problem. However, fiber cables are very delicate and deploying fiber when there's copper you can use is an expensive luxury. LAN cables made up of copper wires Technically, ...


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