The Central Station Plus units have a functioning footswitch port (for momentary Latching/Non-Latching) switches that enable the Talkback microphone on the face of the Central Station and a connected, enabled External Microphone input. Based on the design, it will not enable the Remote talkback source with the Footswitch, but it may illuminate the button itself making it seem like the microphone is available to be used.
As the schematic shows from the Central Station Manual, The talkback source is not part of the signal path for the microphone, as it has a completely different path all together. The source deviates and in firmware, the microphone is disabled the moment a footswitch is engaged.
