DTMF, via touchtone phone, does not require Internet access. It has the same functionality as the Moderator tool.
During the conference, press "*"plus:
* - Repeat menu options
0 - Transfer to Operator
1 - Mute or unmute this line
2 - Participant count, followed by roll call
3 - Turn on or turn off Lecture Mode
4 - Lock or unlock conference
5 - Recording submenu
6 - Invite a new participant by calling the participant
8 - End conference
# - Return to the conference
Participants can use the Mute/Unmute command.