Message header

Properties

The message header is mandatory and contains the following properties:

Property	Description
ProtocolVersion	ECR performs terminal discovery to get a list of terminals it has access to, using synchronous request.
MessageClass	Enum: Service, Device, or Event
MessageCategory	Enum: Login, Logout, CardAcquisition, Payment, StoredValue, BalanceInquiry, Reconciliation, TransactionStatus, Diagnosis, Abort, EnableService, Reversal, Display, PIN, Event, Input
MessageType	Enum: Request, Response, Notification
ServiceID	Identification of a service message pair message pair
DeviceID	Identification of a device message pair. Only used for messages with MessageClass=Device
SaleID	Identification of the ECR system. Note: the value used in this field must match the value used in the 'saleName' parameter in the connection string.
POIID	Terminal ID

Message identification

Messages are identified by the data elements ServiceID and DeviceID of the MessageHeader. See 2.2.5 Identification of Message Exchanges in [1] for additional information.

ServiceID and DeviceID is of type string with length: 1-10. It should be unique per service or device dialogue (request+response pair). As a practical reccommendation to make log reading and troubleshooting easier, is to use a sequential numeric ID. This makes it easy to spot mismatches when reading logs.

Message extensions

Aera has made some extensions (additional fields) to the Nexo messages in cases where no suitable fields exist in standard Nexo. Such extensions are prefixed with 'Ae' to make them easily recognisable.