Rail Industry Guidelines for EDI: Introduction and Overview
Data Element Separators and Terminators
Data Element Separators
Each data element in a segment is preceded by a separator character which is identified in the interchange control header as the delimiter between data elements. The data segment identifier and the first data element are also separated with this character. Within the guidelines of the rail industry the “*” will be exclusively used for this purpose, and, therefore, an “*” will not be permitted in any other area or portion of a transmission.
Data Segment Terminators
Each segment ends with a segment terminator which is identified in the interchange control header as the end-of-segment marker. Within the guidelines of the rail industry, the EBCDIC HEX 15 will be exclusively used for this purpose.
A functional acknowledgment is the transmission of Transaction Set 997 to the original sender to indicate the status of the transmission with respect to standards adherence. The acknowledgment does not imply acceptance of the contents (price, terms, etc.) of the associated transaction sets. It is the responsibility of the sender of the transmission to assure that it is received and syntactically accepted by the receiver.
The functional acknowledgment provides a syntactical indication that all transactions transmitted were received and, if errors exist, to identify the EDI segment and rejected elements and reason for error.
The rail industry requires acknowledgment of all transmissions initiated by a railroad and intends to acknowledge all which originate with its supplier. (The obvious exception is that functional acknowledgments are not acknowledged.)
If a functional acknowledgment transaction set is received with functional errors or cannot be related to a previous transmission, it should be printed for manual resolution.
Syntactical errors are reported in the Transaction Set 997. Some types of errors detected include:
- Incorrect data type
- Incorrect field length
- Missing information
- Unrecognized code
- Incorrect segment identifier
- Special requirements not met
The rail industry expects that the sender will edit each transmission for compliance with the X12 Standards and, furthermore, the recipient is expected to do the same.
Retransmission of Transaction Set
Transaction sets accepted with reported errors are not retransmitted.
It is recommended that the rejected transaction sets be retransmitted in full after corrections are made. If correction and retransmission of rejected transactions is not possible, the sender may use manual means external to the data interchange process.
Accepted transaction sets are never retransmitted even when they are within a functional group which may have contained one or more rejected sets.