Kramer Electronics VS-4228 VS-4228 is a high performance bi-directional matrix switcher for RS-422 control signals. It can connect multiple ports to create from one to four bi-directional communications groups. Control - Front panel, RS-232 (K-Router Windows - based software is included), and RS-485. Memory Locations - Store multiple switches as presets to be recalled and executed when needed. Front Panel Control Lockout. Standard 19inch Rack Mount Size - 1U.