If you are asking how to block Operator Assited calls out of your building you would do DIS-LDPLN and look for entries I assume that would start with "9-0-etc" and look at what privilege is necessary to dial that sequence. Make sure the LCRCOSV of the users you want to block do not include that privilege level.
It may be more than that depending on how complicated your dialing rules are.
If you are talking about how to keep people from charging collect calls to your building (because people accept the charges) you have to block that through the phone company.
Don Bruechert, Voice Comm Analyst II
CareTech Solutions @ Holy Family Memorial
Manitowoc, WI, USA