International telephone calls are routed via a Turkish dialling code (+90 392) as Northern Cyprus has neither its own country code nor official ITU prefix. Similarly with the internet Northern Cyprus has no top level domain of its own and is under the Turkish second-level domain .nc.tr. Items of mail must be addressed 'via Mersin 10, TURKEY' as the Universal Postal Union does not recognise Northern Cyprus as a separate entity. Amateur radio operators sometimes use callsigns beginning with "1B", but these have no standing for awards or other operating credit.