Telephone numbers in Turkey former area codes other than the primary one mentioned. The country calling code of Turkey is 90. trunk / inner - city code number : 0 international code : 00 Ankara DMS-300 Istanbul DMS-300 İzmir DMS-300 Ankara, İstanbul and İzmir DMS-300 International Exchanges Accept: L/D + area code + subscriber number + ST L /D = language digit : 0 (direct dialing) L /D = language digit : 2 (operator assistance) There are two international operator centers in Turkey, Ankara and İstanbul. Each one of these centers provides operator telephone services according ITU/T dialing: L/D + code11 + ST (Random)
Circuit identification code Circuit identification code The ISDN Services User Part (ISUP) Circuit Identification Code (CIC) is part of the Signaling System #7 which is used to set up telephone calls in Public Switched Telephone Networks. as part of the Initial Address Message (IAM). When a telephone call is set up from one subscriber to another, many telephone exchanges will be involved, possibly across international boundaries. To allow a call to be set up correctly, where ISUP is supported, a switch will signal call-related information like called or calling party number to the next switch in the network using ISUP messages. The CIC