Meetme will allow us to create conference rooms very easily, but keep in mind that this will consume a large number of resources in the system.

We create the room taking into account the syntax:

Usage is conf => confno[,pincode][,adminpin]

[rooms]
conf => 600,54321

In the extensions.conf

exten => 000,1,MeetMe(600)

When 000 is dialed, it will try to enter conference 600 by asking for a password, with the password being 54321.

You can know the number of people present in a conference:

exten => 601,1,Playback(conf-thereare)
exten => 601,n,MeetMeCount(600)
exten => 601,n,Playback(conf-peopleinconf)

Controlling the maximum number of people in a conference, in this case, we also record the conference:

; limit the conference room to 10 participants
exten => 600,1,MeetMeCount(600,CONFCOUNT)
exten => 600,n,GotoIf($[${CONFCOUNT} <= 10]?libre:lleno)
exten => 600,n(libre),SetVar(MEETME_RECORDINGFILE=/var/spool/asterisk/meetme/conference_recording-${EPOCH}-${USER})
exten => 600,n,MeetMe(600,r)
exten => 600,n(lleno),Playback(conf-full)

NOTE: The conference has been recorded thanks to the r parameter of: MeetMe(600,r)