The blacklist represents itself a list or register of entities which are denied privileges, service, mobility, access and admission due to these or other reasons. This function blocks all connections from the subscribers who are in the list.
Telephone service companies have created a special communication service without the need to use customer's equipment. It's called a "virtual number". It also has a text type of "virtual SMS center." Thanks to the virtual link you can make calls or send messages while connected to the equipment of the company.