During the conference carrying-out the operator can perform all controlling operations such as adding new and deleting existing conferees, changing their status, stopping the conference from the telephone without dependence on when and how he has entered the conference. All operator's commands begin with the "0" digit which is followed by the <operation code> and <internal number of a conferee>. For acceleration of the input, the commands can be terminated by pressing the "#" key (telephone analog of "Enter"). The following operation codes are possible:

• 1 - To add a conferee, i.e. to call him up and to connect him to the conference (for example, the "015678" command means to call up the conferee having the 5678 internal number).
• 2 - To delete a conferee from the conference (for example, the "027484" command means to delete the conferee having the 7484 internal number).
• 3 - To change the status of a conferee (for example, the "035678" command means to change the status of the conferee with the 5678 internal number from active to monitor/simplex or vice versa. And if the subscriber is absent, the system tries to add him, i.e. calls up to him).
• 4 - To stop the conference.

Any conferee just like the operator (in case the system was not able for some reason to get him by phone at the conference start-up, or because he has hanged up and has left the conference) can at any time call the system at the known phone number to join the necessary conference after authorization according to his status, that is preset by the operator. Moreover, each conferee, - if the appropriate option is switched on in the conference settings by the operator, - can dynamically change his status by pressing the "#" key on the phone key-pad. In so doing the status change of the conferee from active to monitor/simplex conferee occurs always, but from monitor/simplex to active only when a free conference resource is available, otherwise the status remains unchanged.