6bf131c7__x____About_Licenses___DocWiki__Description
[License] stdvoiceconf [Description] 
The stdvoiceconf license limits the number of concurrent standard (ad hoc) voice conferencing participants. This number may be further limited by the maxstd license. If you do not install the stdvoiceconf license, the system can use only the six trial voice ports for standard (ad hoc) conferencing.
Cisco Unified MeetingPlace Express, Release 2.x -- About Licenses - DocWiki