Rj45 to USB?
RJ45 to usb 3.0 reliable on home network?
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I have one of them, however, I dont really get how it is possible for it to be implemented.
USB has two data lines and RJ45 can have more than 2. So, how is it so easy to be converted one to the other?
Is there any specification practice or common implementation that helps it to be like this?
I was thinking that maybe both use a buffer for transferring data, so it's a matter of changing the rate of transfer and that's all (Depending of the number of pins.) I'm guessing here. Some guide would be appreciated!
That RJ45 to USB cable is not an Ethernet adapter.
It might superficially look like one, but it’s not.
That cable you purchased is a known as console cable (aka: Cisco cable or rollover cable). It’s meant/designed to connect your PC to a server (or other enterprise level device) via RS232; aka serial connection or link. That is not an Ethernet adapter, and cannot be used as one at all.
Generally, what you are looking for is a USB to Ethernet adapter that looks something like this:
You would plug the USB side into your PC and then connect the Ethernet end to your LAN via an Ethernet cable. These are fairly common to come by and should be pretty affordable. Just make sure to check if the USB A to RJ45 adapter you purchase explicitly states it’s an Ethernet adapter.
The 8P8C connector (commonly known as RJ45, even though this is incorrect) is used for a lot of different things.
While nowadays its most common use is for (some kinds of) Ethernet, it can also be used:
- For RS-232 or other similar serial ports (instead of the more common DB-25 or DE-9 connectors), especially for console access on Cisco routers and other devices;
- For analogue telephony (aka POTS);
- For digital telephony (aka ISDN);
- For proprietary telephony systems;
- Sometimes even USB;
- And many other things.
The adapter you bought is for the first type: to connect to an RS-232 serial port presented as 8P8C (RJ45). It is completely unrelated to Ethernet.
What you need is a USB Ethernet adapter. They come in many different shapes and sizes, and have varying characteristics and performances (100 Mbit/s, Gigabit, 2.5GbE, USB 2, USB 3, USB-A, USB-C...). You need to make sure the description of the product includes "Ethernet", along with the specs you want.
Some docks (especially USB-C docks) also include Ethernet ports, so it may be an alternative if you need other interfaces (more USB, HDMI, etc.).
If your computer has a USB-C port, you're probably better off using an adapter using that kind of port. Given the low prices of such adapters, picking a 2.5GbE adapter is probably a good idea even if you won't use it at its maximum potential if your switch/router doesn't support such speeds.
While there are a few adapters that take the form of a cable (with a male "RJ45" at the other end like the one you bought), most will have a female connector, and you will then need an Ethernet cable to connect that to the corresponding connector on your switch or router. The advantage is that you can easily change the cable if you need shorter or longer distances (or if the cable or plug gets damaged).
I am looking to repurpose a mini pc to a OPNsense firewall/router, then add a managed switch. Are the RJ45 to usb 3.0 adapters reliable enough for this application? Thanks for any advice!