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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 ...


3

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-...


2

What doesn't emerge clearly is the detail about the physical location of the NID. Is it (at least typically, if such a typical implementation exists) in the operator's access network's footprint? Is it in the customer's premises? The physical location of the NID will vary. At some sites, it can be located in the customer premises, just like the telco ...


2

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 (...


2

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 ...


2

That is when someone says: "The data is transferred over Ethernet" They are saying: "The data is transferred over a LAN/MAN with Ethernet/Twisted Pair cabling using the Ethernet protocol" This is not necessarily true. The term "Ethernet" is a victim of networkers' propensity towards overloading and/or abusing terms. If someone ...


2

Practically, all of the above. Ethernet is a family of protocols. All of them use a common definition for the data link layer (OSI L2), with some variations. The numerous physical-layer variants (OSI L1) cover practically all use cases - twisted-pair copper for cheap, flexible uplinks (including single pair), fiber for medium and long reach interconnects, ...


2

Ethernet is a family of layer-1/2 protocols that run on a variety of media, from the original coax bus to the latest fiber optics. Ethernet was created by Robert Metcalfe as a college project, and it is now maintained by the IEEE 802.3 working group. It has many different standards for various speeds on different media. HDLC runs on the (almost) obsolete TDM ...


1

There was a level 2 ping equivalent in the original Ethernet 2 specification. It was the Loopback option in the Ethernet Configuration Testing Protocol, and was mandatory, However, it was not adopted when the IEEE standardized Ethernet as 802.3. DEC supported it on their machines, and it was sometimes useful to check network connectivity to systems where the ...


1

An addendum for the reference: rfc5226 speficies IANA registry for ARP


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