welcome to the Polycom Community.
The Serial is usually 12 or 14 digits and usually starts with an 82
In addition do you have any details ? i.E. is this a new or used unit?
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Polycom Global Services
If the serial number is not as explained in the previous response you should open a service report with your service provider for that unit. They will need to make a determination on the appropriate action to resolve your issue.