From 00:00 of 21 July, 2005 (Tehran Local Time), whatever the first digit of the previous 7-digit telephone number is, duplicate it at the beginning of the number to get 8 digits. E.g. 234 5678 will be 2234 5678 or 876 5432 will be 8876 5432.

   The change does not apply to telephone numbers started with 811, 329 and 520. And also does not apply to 3-digit service telephone such as 119 and 117.