The Carrier Identification Code
(CIC) or the Carrier Selection Code (CSC) is the network prefix that every network operator has, hence the German name Verbindungsnetzbetreiberkennzahl (VNBKZ). The interconnection networks are the networks that interconnect subscriber networks. The number range of the interconnection networks is defined in ITU Recommendation E. 164. Each network operator has its own five-digit CIC code, starting with 010. For example, Deutsche Telekom has the CIC code 01033, T-Mobile 01071, Vodafone 01070 and 01072.