The Room Kit Pro is a device that has the ability to set a mono output if that is helpful in deciding which device to purchase to meet your requirements.
The Room Kit Plus does not have the ability to set this, you will need to do a mix on external audio equipment to get a mono output.
In general, audio from the participants in the meeting will be mono anyway - it's just any content that is fed in to the system that may be in stereo, so depending on what you are trying to achieve, the standard output may be alright for if that matches your requirements.
Wayne
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