The ST-GSP1 is a gated speech preamplifier designed to be used in a variety of situations where it is desired to produce an automatically switched line-level signal from a microphone. This module may be used in conjunction with other RDL modules to configure automatic mixing systems or may be used alone as a voice-operated module. The open-collector slave output may be used to trigger other equipment or RDL modules. The versatility of ST-GSP1 applications range from complete automatic mixing system design to the addition of automatic mic gating to the inputs of conventional mixers or amplifiers.