With DDM (Dynamic Device Mapping) Technology, the communication between shared peripherals and all connected systems are maintained 100% of the time, even as a user switches between the KVM ports.
Many USB KVM devices provide peripheral emulation, sending signals to the computers that are not currently selected to simulate a keyboard, mouse and monitor being connected.
In addition, some types of computer systems do not treat USB devices as hot-pluggable, which means the keyboard and mouse will not be re-detected when switching back to a particular KVM port.
When emulating a USB keyboard, mouse, and monitor it is impossible for most KVM's to simulate various types of I/O devices specifically.
As a result, KVM switches will sometimes offer inconsistent performance and even sometimes unsolved compatibility issues with the shared keyboard, mouse, and other devices.