I have an old MasterView CS104 KVM switch sitting around, still in working condition but without support for USB peripherals. The ports it offers are:
- PS/2 or DIN keyboard (the switch acts as a passive adapter on each port, thus connections can be mixed)
- PS/2 mouse
- Serial mouse
Switching is done electronically: press a button on the switch to cycle through the connected computers. This can also be done via certain key combinations on the connected keyboard, which means the keyboard signal definitely gets intercepted in the switch.
No translation is done between the two mouse port types; the manual states that if the computers use a mix of PS/2 and serial mice, a mouse of each type must be connected to the switch.
Now I am wondering if there is a way to “bolt on” USB support by adding passive homebrew adapters to the mouse ports (either the PS/2 or the serial ones). Will this particular type of KVM switch pass the data lines as well as the supply voltage in the intended manner? Would I need to use specific pins for specific signals?
Note: I am aware of active adapters that allow a PS/2 keyboard and mouse to be plugged into a USB port (with protocol conversion), as well as the inverse for at least some mice, but this is not my question.