How does a network adapter distinguish between twisted pair category?

Question

Computer networks

I honestly googled, but they only give me information on the categories themselves.

Faced with the fact that I changed the provider and the tariff plan from 100Mbps to 500Mbps. At home back in 2010, during repairs, ethernet sockets were switched, but when a computer was connected, the speed remained 100 Mbps. If you take a fresh patch cord and connect it directly to the router (the ports are all gigabytes), then it shows 1 GB.

As a result, I decided that it was possible that during the repair they cheated and stretched a cable of the fifth category to the sockets, but how does a computer or router understand that this is not cat5e? Or, perhaps, when connecting sockets, the contacts were connected under 100 Mb / s, that is, only two pairs of four? On the socket itself, you can see 8 contacts, if anything.

As a result, I threw a cable from the router along the baseboards, but the question still haunts me.

Answer 1

He does not distinguish the category in any way, the network connection passes the speed negotiation, with 2 pairs - 10/100Mbps, with 4 pairs - 1Gbps, if at least one core out of 8 is damaged - gigabit will not rise

Answer 2

I agree with Drno.
I'll add a little.
When measuring a speedtest, it is necessary to measure it to the network of another provider or to a neighboring region.
Within its network, the provider will show you such cosmic speeds that it’s expensive to watch, but in reality you will never see them during operation.
Example:
Within the provider's network -
To a neighboring country -

Answer 3

They laid a twisted pair of 4 wires instead of 8
You laid 8 wires - but in some place they divided it into 2 cables of 4)))
Well, it’s not the question - why do you need 500 mb at home if it’s not a secret?) Especially if this is a thread from Gosovskikh - like Rostelecom or Dom ru, you won’t see these 500mb ... it gave out at least 100, it will be good)
More precisely, the speed test and other speed meters will show 500, but in fact to the same Europe, for example, especially in the evening it will be at times less ... unfortunately I came across in more than one place (