Will there be any problems with a Y-shaped twisted-pair connection?

Question

Cables and wires

There was such a situation that I got a job to work in a new place, and now I got to network rewiring ... The point is
that half of the office sits through Wi-Fi, and the other half sits through cat5 (not cat5e), and this is not good! And the cable channel in the office is clogged! And then the thought came to me that it is possible to run 2 devices at once on one wire, and then everything turns out beautifully and you don’t have to redo the cable channels. It turns out that 2 pairs per 1 device converge into 1 cable and at the output we have either 2 connectors, or 1, but in which there are 2 devices in the neighborhood at once. I use the sequence (1¹,2¹,3¹,6¹)->(1³,2³,3³,6³), (1²,2²,3²,6²)->(5³,4³,7³,8³). Will there be any serious problems with such a connection, or is it better to separate it into 2 connectors?

Answer 1

Indeed, using a 2-pair connection will allow you to connect twice as many subscribers through the same number of cables, losing only in channel bandwidth - instead of one gigabit, you will get two 100-megabit channels on each cable.
If your network is used mainly for distributing the Internet, then you can do this. If a gigabit connection is really used (i.e. there is processing of large arrays over the network at high speeds, there are thin clients in the network, etc.), then it’s better not to do this, because people will complain about the speed drop.

(1¹,2¹,3¹,6¹)->(1³,2³,3³,6³), (1²,2²,3²,6²)->(5³,4³,7³,8³).

What this might mean is not clear. I use the usual 568B pinout, orange and green pairs in one channel, and blue (as a replacement for orange) and brown (as a replacement for green) in the other.

Answer 2

A very bad idea. Instead of a gigabit network, there will be only 100, there may be problems on long links. If there are really not enough sockets in the SCS - unmanaged switches where it is needed. Something like D-Link DGS-1008D. These have been working for years and cost 3 kopecks. You can look at options with POE to power let's say sip phones or wifi points.

Answer 3

I did not come across a cable of the fifth category, only 5e, although I started working with coaxial networks. The fifth category is not certified for a gigabyte connection, and in a four-pair cable, additional pairs were used for analog telephony. 5e allows gigabit connectivity. I had to use the connection described by the questioner. As often happens, they approved the project for placing Ethernet sockets in the premises, the cable was laid, and then suddenly it was necessary to organize more jobs, the deadlines were running out, laying the cable - it was necessary to disassemble the ceiling and cable channels, I had to connect two jobs via one cable. It's okay, the office rarely needs a gigabit connection between all the hosts, even when constantly working with databases.
As for the compliance of the cable parameters with the specification of the category defined in ANSI / TIA / EIA - marking the cable with a certain category does not indicate its quality, you must carefully choose the manufacturer and not save even when laying a temporary network in a small office, so as not to encounter a number of problems , which cannot be solved otherwise than by replacing the entire cable network.