Do you mean KVM switch - i.e. to switch between main and backup?

or

KVM extender - to extend the Keyboard Monitor and Mouse over cat5 to FOH?

or combination of both?

they are 2 distinctly different products...

most of the adderlink range is good, depending upon signal types and distance.
(avoid the infinity series - It doesn't work...)

gefen is also cheap...

There are many serial controlled matrixes on the market, which either catalyst could control
available in 2 way or 4 way depending what you need to do...

S