Telephone numbers in Luxembourg employ a closed dialling system, whereby all numbers are dialed in the same format whether from within Luxembourg or from abroad. There is no trunk like "0". The incumbent operator employed an open numbering plan with numbers of varying lengths, where a two-digit area identifier is followed by one to four digits, all 6 digits formed the subscriber number. This was changed by the introduction of a new numbering plan in 1999. Telephone numbers introduced since May 2000 by the incumbent operator begin with "2" (generally 26, 24 and recently 27) followed by two to 6 digits. The area identifier is still present and generally following the 26, 27 or 24, however numbers can be taken to any other area.