IEC 62343-4-1:2016(E) describes and provides specifications for a software and hardware interface for the 1 x 9 wavelength selective switch. These switches can be controlled by resident firmware with this interface. This standard addresses the configuration and function to control a WSS. This interface is intended to enable a user or host to retrieve the switch status and/or adjust relevant switch and attenuation settings. Keywords: wavelength selective switch (WSS), reconfigurable optical add drop multiplexer (ROADM), dense wavelength division multiplexing (DWDM)