The ACH File Documentation Screen explains the output format used for AAR processing (which produces PAR output files). The output format uses the ACH (Automated Clearing House) standard defined by NACHA (the National Automated Clearing House Association).

Records in the ACH format are 94 characters long. The record type is identified by a digit in column 1 (click a digit to jump to the corresponding section):

'1' = First line of file

'5' = First line of a batch (also known as a “transaction-set”)

'6' = Second line of a batch

'7' = Third line of a batch (see note)

'8' = Final line of a batch

'9' = Last line of file