Programme Identification (PI) is a service provided by radio stations transmitting Radio Data System (RDS) data as part of the FM radio broadcast. It is 4-digit hexadecimal number.The PI code allows the radio to identify the station across different broadcasts / multiplexes. For example BBC Radio 1 has PI C201. It is also used in Digital Audio Broadcasting as Station ID. PI is globally unique only in combination with ECC (extended country code). PI code (station ID) is usually not displayed on the radio receivers. The PI Code is also used by the RadioDNS standard.