MeetMe conferencing with Call Manager Express allows a CME phone to go off hook, press the MeetMe softkey, and dial the MeetMe bridge number to start a conference. Any other CME subscriber or off-net party may dial the MeetMe number to join the conference.  By default CME does not play tones when participants join or leave the bridge. Adding this capability requires the creation of a voice class for both the join tones and leave tones where tone frequencies are defined and then later referenced in the dspfarm profile.  In order to perform the following configuration you should already have hardware conferencing configured on CME.  Reference this post for assistance.

1. Configure a number to be a MeetMe Conference Bridge

ephone-dn  10  octo-line
number 4454 no-reg primary
conference meetme

2. Configure an ephone template that includes the MeetMe Softkey. This is so CME subscribers can easily start a conference.

ephone-template  1
softkeys remote-in-use  CBarge Newcall
softkeys seized  Redial Endcall Meetme Pickup Gpickup Cfwdall Callback
softkeys connected  Hold Endcall LiveRcd Park Trnsfer Confrn

ephone  1
privacy-button
mac-address 0022.90BA.2CC0
ephone-template 1
busy-trigger-per-button 4
button  1:1 2:2

3. Configure the appropriate voice class to define Join/Leave tones

voice class custom-cptone conf-leave
dualtone conference
frequency 300 900
cadence 300 150 300 100 300 50

voice class custom-cptone conf-join
dualtone conference
frequency 600 900
cadence 300 150 300 100 300 50

4. Assign each voice class to the dspfarm profile used for conferencing

dspfarm profile 1 conference
codec g711ulaw
codec g711alaw
codec g729ar8
codec g729abr8
codec g729r8
codec g729br8
maximum sessions 2
conference-join custom-cptone conf-join
conference-leave custom-cptone conf-leave

associate application SCCP