Sonifex RM-2S4 4 Stereo Channel Input Reference Monitor with 2 LED MetersThe RM 2S4 is a 1U rack mount unit offering quality loudspeaker monitoring and accurate, high resolution metering of up to four stereo audio sources and more with the addition of optional expansion cards. Sources may be in any mixture of analogue and AES EBU digital formats, with sample rates up to 192kHz accepted. Audio inputs on the RM 2S4 can be analogue or digital because they are autoswitching using the left Neutrik XLR for AES EBU, or both