I'm not able to select the T.120 option within the services profiles on my 3515 MCU. The services are not SCCP enabled (SCCP isn't enabled on the MCU either) so I'm not sure what the problem is. Any suggestion is appreciated.

I am trying to achieve the following setup:A "master" phone goes off-hook and the system automatically dials multiple (say 10) phones. As those users pick up they are all dropped into the same conference with two-way communication with all others. ...