When reviewing your conference reports via either your invoice details or our Customer Portal or even post-call email reports, you may occasionally see Unknown Number listed rather than a telephone number.  This means that participants joined via either a VoIP phone or their number was blocked by the telecommunications carrier or that individual has taken action to prevent their identity from being known.  Pragmatic is unable to directly control Unknown Numbers from appearing in your conference reports.  We also would not be able to provide details on the person calling from the Unknown Number if we were asked to do so after the fact.  As a best practice, we suggest you do a Roll Call while conducting your conference call so that you can confirm your participants on the call.