Polish wireless operator Polska Telefonia Cyfrowa (PTC) has launched a number portability service, enabling the transfer of numbers between networks. The service is currently only available to post-paid customers. In order to transfer a number to another mobile network a subscriber must first obtain confirmation of technical compatibility from the operator to which the number is to be transferred, establish the conditions for termination of the agreement with the current operator and sign an agreement with the operator to which the number is to be transferred.