Field	Expected value	Description
MTID	0100	Identifies the message as an authorization request.
Txn_Type	A	Identifies the transaction as an authorization.
Txn_Stat_Code	A, when present	Indicates authorization transaction status context.
Authorised_by_GPS	N or Y	Indicates whether authorization was performed before the message reached the external host flow.
SendingAttemptCount	Varies	Indicates the sending attempt count and may help identify repeated delivery attempts.