As of tomorrow, Sunday, phoning anyone in Greece will involve a longer process. All numbers will acquire three to five extra digits. The changes, whose purpose is to expand network capacity and allow the future creation of alternative networks, will affect all fixed-line phones – but not mobiles – and apply to both local and long-distance calls. But existing numbers will remain essentially unaltered. Callers will have to dial the area code (01 for Athens, 031 for Thessaloniki and four-digit for most other parts of Greece) followed by the digit 0 and then the old number. Callers to Greece from abroad will have to do the same, though the country code remains 0030. (Calling Athens from abroad will entail dialing 0030-1-0 and then the old number).Callers trying the old numbers will hear a message explaining the new system.