I want to connect several computers (like desktop and notebook) to several monitors to have a big desktop on both.
What hardware device do I need?
If I connect a HTMD/USBC "joiner" which has many inputs and one output, to a "splitter" which has one input and many outputs, will it work (in common case)?
If you want one computer connected to each display: you can use a software like Synergy to share one keyboard and mouse between the two.
If you want one computer connected to both displays, one at a time: the easiest way is to just run two cables to each monitor utilizing the multiple input ports. For convenience, you can get a display switch.
If you want to swap what is displayed on a mixture of displays, you can use a display "matrix". This will allow you to have multiple inputs an swap them from monitor to TV etc.
A display splitter will duplicate what is sent from your computer to two different displays, showing the same image twice.
A KVM is the holy grail and will switch both your USB devices (keyboard mouse) and multiple monitors from one computer to another, but they are much more expensive. They are also becoming more rare as data throughputs are getting higher, and most industries are switching over to softwares like Remote Desktop or VNC, instead of KVMs.
It can be very difficult to find something that fits your exact set of computers and monitors, but hopefully knowing some of the terminology will help.
t's depending on how the makers define their "KVM switch" can do.
Not everything with four wheels on it can be a real "car".
A lot of very cheap so call " KVM switches" made in China are just "USB hot-pluggable hub"+ hard-wired video connection switches - they can be as cheap as under $50.
It can be very expensive if the KVM switch can do full-time EDID emulation to all connected systems, USB HID emulation for no-latency HID device sharing, keep-alive HID to all connected systems, serial controls via RS-232 port (for most industrial applications required), independent video switching/ port parking/ port locking, native full-bus DisplayPort 1.4 protocol link trains for full-range of color space application ...etc.
Anyways, for example, a two-port KVM switch can be ranged from sub-50 to $500+. It is all depending on what you're looking for and what can be done for one's application needs.
