The following settable channel variables are not referenced in the code: conference_input_buffer_flush_msec, conference_output_buffer_flush_msec, conference_output_discard_low_energy. However, the documentation for the FreeSWITCH mod_conference module describes them as ‘settable channel variables’, which can be set from the dial plan. Hence, to be used, they have to be referenced in the mod_conference modules by their name strings precisely (by calling switch_channel_get_variable).