Chapter 02: Control
This chapter covers the rules that apply to every message. It defines the header, the delimiters and the acknowledgment a receiver sends back.
This chapter defines the rules that every message follows. It defines the message header, MSH, which is the first line of every message. It defines the delimiters that separate fields, components and repetitions. It defines the acknowledgment that a receiver sends back to say a message arrived. It also defines what a receiver does when a message is wrong. Every other chapter depends on this one.
What is in this chapter
- 12 segmentsthe lines these messages are built from, and the fields on each
- 17 code tablesthe value sets the fields in this chapter draw from
- 2 message typesACK, MCF
Message types defined here
ACKGeneral acknowledgment messageNamed by the standard without a structure of its own.
MCFDelayed Acknowledgment (Retained for backward compatibility only)Named by the standard without a structure of its own.
Segments defined here
These 12 segments are defined in chapter 02. Messages in other chapters may still carry them.
ADDaddendum segmentBHSbatch header segmentBTSbatch trailer segmentDSCcontinuation pointer segmentERRerror segmentFHSfile header segmentFTSfile trailer segmentMSAmessage acknowledgment segmentMSHmessage header segmentNTEnotes and comments segmentOVRoverride segmentSFTsoftware segment