grzesiox wrote: ................................Do you know the LAN 10/100 full duplex specifications? two pairs are enough for transmission, because it is on them that the data transfer is carried out.
and..............???? You haven't discovered America

that's exactly how it is
grzesiox wrote:
As for the telephone cable, it is just a twisted pair and imagine that it's better because STP, i.e. shielded in thick rubber insulation and a carrying cable attached with the same insulation
for you every telephone wire is STP??? :)
here's something about your best cable:
Shielded twisted pair STP - has an additional layer of foil or metal wire braiding the wires. The reason for introducing shielding was the need to use twisted pairs in environments susceptible to electromagnetic and radio frequency interference.
In practice, however, this prevents the twisted pair from functioning properly. Electromagnetic radiation is generated when a signal is transmitted over a copper wire. Shielding the cable with a metal sheath protects against external radiation. Unfortunately, it also stops induced radiation, i.e. radiation produced by this cable when a signal is sent through it. So, instead of propagating normally, the radiation is reflected by the shield and directed back to the copper wire, which is likely to damage the signal.
grzesiox wrote:
Another thing is UTP twisted pairs - there are so many different twisted pairs that you should look for 2 pairs, what are they for, etc. because I had the pleasure of laying a 2-pair UTP twisted pair many times over long distances and everything works, often on cheap equipment.
and we get to the bottom of it, for what purpose did you put these wires ??

here:
Twisted pair categories acc. European standard EN 50171
Class A - implementation of telephone services with a frequency band up to 100 kHz
Class B - cabling for voice applications and terminal services with a frequency band up to 1 MHz
Class C (Category 3) - covers typical LAN techniques using a frequency band up to 16 MHz
Class D (category 5) - for fast local networks, includes applications using the frequency band up to 100 MHz (100 Mb/s) Class E (Category 6) - is the latest (1999) extension of ISO/IEC11801/TlA and includes cabling whose parameters are specified up to the frequency of 250 MHz (for applications requiring 200 Mb/s). Implementation of Gigabit Ethernet (4x 250 MHz = 1 GHz) and ATM 622 Mb/s transmission is planned
Class F (category 7) - it is possible to implement applications using the band up to 600 MHz. It differs from previous classes in the use of STP cables (each pair in a shield plus a shield covering four pairs) connected with shielded connectors. Completion of work on the standard is expected in the years 2000-2001. For this class of cabling, it will be possible to implement data transmission systems with speeds significantly exceeding 1Gb/s
Regards[/quote]