A conference system comprising: a control unit; and a plurality of discussion units, wherein each discussion unit of the plurality of discussion units is configured to transmit audio information to the control unit, the control unit is configured to repeatedly transmit and receive a running packet to and from the plurality of discussion units, each discussion unit of the plurality of discussion units comprises: a DU control portion, a microphone, and a DU communication portion, the DU control portion is configured to add a request flag corresponding to a speech request to the running packet, the DU communication portion is configured to transmit the running packet, with the request flag added, to the control unit, the control unit comprises: a CU storage portion, and a CU control portion comprising a plurality of audio slots, each audio slot being configured for receiving audio information from a discussion unit of the plurality of discussion units, wherein the number of audio slots corresponds to the number of discussion units that may be enabled for speech at the same time, the CU storage portion is configured to store control information for controlling operations of the control unit and each of the plurality of discussion units, the CU control portion is configured to assign an audio slot of the plurality of audio slots to the discussion unit of the plurality of discussion units that transmitted the running packet with the request flag added, the control information includes: addition mode information, specifying an addition mode related to a setting of a trigger for turning on the microphone, among a plurality of addition modes for adding the request flag to the running packet, the setting of a trigger being either an automatic trigger or a manual trigger, and assignment mode information, specifying an assignment mode related to an on/off setting of an override in the assignment of the audio slot, among a plurality of assignment modes for assigning the audio slot of the plurality of audio slots to the discussion unit which transmitted the running packet with the request flag added, when the audio slot of the plurality of audio slots is not vacant, and the addition mode information is stored in the CU storage portion in association with the assignment mode information. a control unit; and a plurality of discussion units, wherein each discussion unit of the plurality of discussion units is configured to transmit audio information to the control unit, the control unit is configured to repeatedly transmit and receive a running packet to and from the plurality of discussion units, each discussion unit of the plurality of discussion units comprises: a DU control portion, a microphone, and a DU communication portion, a DU control portion, a microphone, and a DU communication portion, the DU control portion is configured to add a request flag corresponding to a speech request to the running packet, the DU communication portion is configured to transmit the running packet, with the request flag added, to the control unit, the control unit comprises: a CU storage portion, and a CU control portion comprising a plurality of audio slots, each audio slot being configured for receiving audio information from a discussion unit of the plurality of discussion units, wherein the number of audio slots corresponds to the number of discussion units that may be enabled for speech at the same time, a CU storage portion, and a CU control portion comprising a plurality of audio slots, each audio slot being configured for receiving audio information from a discussion unit of the plurality of discussion units, wherein the number of audio slots corresponds to the number of discussion units that may be enabled for speech at the same time, the CU storage portion is configured to store control information for controlling operations of the control unit and each of the plurality of discussion units, the CU control portion is configured to assign an audio slot of the plurality of audio slots to the discussion unit of the plurality of discussion units that transmitted the running packet with the request flag added, the control information includes: addition mode information, specifying an addition mode related to a setting of a trigger for turning on the microphone, among a plurality of addition modes for adding the request flag to the running packet, the setting of a trigger being either an automatic trigger or a manual trigger, and assignment mode information, specifying an assignment mode related to an on/off setting of an override in the assignment of the audio slot, among a plurality of assignment modes for assigning the audio slot of the plurality of audio slots to the discussion unit which transmitted the running packet with the request flag added, when the audio slot of the plurality of audio slots is not vacant, and addition mode information, specifying an addition mode related to a setting of a trigger for turning on the microphone, among a plurality of addition modes for adding the request flag to the running packet, the setting of a trigger being either an automatic trigger or a manual trigger, and assignment mode information, specifying an assignment mode related to an on/off setting of an override in the assignment of the audio slot, among a plurality of assignment modes for assigning the audio slot of the plurality of audio slots to the discussion unit which transmitted the running packet with the request flag added, when the audio slot of the plurality of audio slots is not vacant, and the addition mode information is stored in the CU storage portion in association with the assignment mode information.