The function feature "the hidden room" is that it only works on mobile phones. That is, the equipment operator, regardless of whether the function of anonymity on the mobile phone of the caller or disabled, detects every phone call and every number he performed. Therefore, in order to determine the hidden number of a caller, contact the helpdesk of your mobile operator.
If personal visit, show managers your passport, confirming thus their right to conduct operations with the subscriber phone number. Then order Manager service "detailed account". Maybe it will cost some money, who usually are debited from the account your phone after this service.
After the Manager will print the details of an account over a selected period of time, all you need to determine the number of hidden – just find a match on the date and time of the anonymous call in the report. Near the time of each call is the number from which the outgoing call. Thus, you will only see the anonymous phone caller.