# serviceId

val serviceId: String? = null

Identification of a data pair, which processes a transaction

It allows a unique identification of a data pair, between a Sale System/Terminal and a POI System/Terminal during period of time, typically one day. The receiver of a request data has to check that this idenfier has not the same value than the last one for the same initiator. This identifier is mandatory for messages of the "Service" and "Event" MessageClass. This identifier is mandatory for messages of the "Device" MessageClass, if the request comes from the POI. This identifier is absent for messages of the "Device" MessageClass, if the request comes from the Sale. The ServiceID of the data response is always the same value than the ServiceID of the data request. This identifier allows the recognition of duplicate data and association of a data response to its data request. Value of ServiceID could be a structured string of alpha characters, for instance with a prefix to easily distinguish a particular sequence of messages. In a TransactionStatus, the data body contains the ServiceID value which identifies the "Service" data exchange to enquire