Since when do computers only have one hole capable of fitting an RJ-45? What ghetto ass rigup do you have?
There should be an input and an output.
Ummm...
since the LAN cable was invented. Hell, since Telephones were invented. When was the last time you saw TWO slots on the back of a phone that only accepted one line?
The input and output are in the same cable. There are 8 copper wires inside each cable. Those wires transmit and receive data.
Yes they do. I take it you haven't looked at the back of your computer recently? Most computers are setup to allow them to bridge connections to other devices, this requires two separate ports, one for connecting to a router (the input) and one for connecting to another computer (the output).
I find it funny that at the same moment you are announcing the intuitiveness of a system, you are misunderstanding the subject because the way things are labeled is misleading. Does that perhaps mean that the system is not in fact intuitive?
I'm an expert at computers. I look at the back of computers on a daily basis, built many of them, and setup roughly 300 separate desktop machines personally. And I hate to tell YOU but most computers are NOT setup to bridge between two devices. The only ones that you might see are dial-up modems, which allow you to have a phone line pass-through to a phone.
When a computer wants to connect to another computer it will most likely use the LAN jack (or Ethernet port if you wish). It goes from the computer to a router and from the router to another computer. Why on Earth would you make a computer a pass through when you don't need to? Can it be done? Sure. I've got 2 LAN ports on my motherboard. Doesn't mean I one of them is strictly output and one is input.
There are other ways, such as the serial port, but that's not widely used outside of direct PC to PC connections (rare) and PC to switch/router interface connections for business networks.
Perhaps YOU are misunderstanding eh?
Let's look at what we've got on the back of a standard computer shall we?
LPT port. (Not usually as they've been replaced by USB)
Serial Port.
VGA or DVI port. (ie. video)
Sound - Line IN
Sound - Line Out
Sound - Mic
USB Ports (various but is at least 2 on modern setups)
(on older computers...)
2 PS2 ports for Keyboard and Mouse.
LAN/Ethernet port.
Some of the computers have more sound ports for surround sound, an extra Video port, maybe even 2 LAN/Ethernet ports.
Here's a nice picture of a motherboard portsAs I said, the ONLY time you're right is if you're talking about a 56k Modem, which has an input and output port but does NOT take an RJ-45/LAN/Ethernet cable but an RJ-8 telephone cable.