Thursday, 25 June 2026

Learning EDI - Day 5: ISA, GS, ST, SE, GE, and IEA Segments in an X12 File

ISA, GS, ST, SE, GE, and IEA segments form the envelope structure of an X12 EDI file. They tell us:

  • Who sent the file
  • Who received the file
  • What type of transaction is inside 
  • Whether the file is complete 

X12 Envelope Structure

ISA
 GS
   ST
     Transaction Data
   SE
 GE
IEA


Example

ISA*00*          *00*          *ZZ*BUYERID*ZZ*SUPPLIERID*260609*1000*U*00401*000000001*0*T*>
GS*PO*BUYERID*SUPPLIERID*20260609*1000*1*X*004010
ST*850*0001
BEG*00*NE*PO12345
N1*ST*ABC HOSPITAL
SE*4*0001
GE*1*1
IEA*1*000000001


1. ISA – Interchange Control Header

The ISA segment is the outermost header of the EDI file.

Purpose

  • Identifies sender and receiver
  • Defines separators
  • Provides interchange control number

Example

ISA*00* *00* *ZZ*BUYERID*ZZ*SUPPLIERID...

Important Elements

Element

Meaning

ISA06

Sender ID

ISA08

Receiver ID

ISA13

Interchange Control Number

ISA15

Test or Production Indicator

Example

ISA15 = T

Means Test Environment

ISA15 = P

Means Production Environment


2. GS – Functional Group Header

The GS segment starts a group of related transaction sets.

Example

GS*PO*BUYERID*SUPPLIERID*20260609*1000*1*X*004010

Purpose

Groups similar transactions together.

For example:

GS
  ST 850
  ST 850
  ST 850
GE

Three Purchase Orders inside one Functional Group.


Common Functional IDs

Code

Meaning

PO

Purchase Orders

IN

Invoices

SH

Ship Notices

FA

Acknowledgments


3. ST – Transaction Set Header

Begins a transaction document.

Example

ST*850*0001

Meaning

Element

Value

ST01

850

ST02

0001

850 = Purchase Order


4. SE – Transaction Set Trailer

Ends the transaction document.

Example

SE*4*0001

Meaning

Element

Value

SE01

Number of Segments

SE02

Transaction Control Number


5. GE – Functional Group Trailer

Ends the Functional Group.

Example

GE*1*1

Meaning

Element

Value

GE01

Number of Transactions

GE02

Group Control Number


6. IEA – Interchange Control Trailer

Closes the entire EDI interchange.

Example

IEA*1*000000001

Meaning

Element

Value

IEA01

Number of Functional Groups

IEA02

Interchange Control Number


How Control Numbers Work

Transaction Level

ST*850*0001
...
SE*10*0001

ST02 must equal SE02.


Group Level

GS*PO*...*100
...
GE*1*100

GS06 must equal GE02.


Interchange Level

ISA*...*999999999
...
IEA*1*999999999

ISA13 must equal IEA02.

No comments:

Post a Comment

Learning EDI - Day 5: ISA, GS, ST, SE, GE, and IEA Segments in an X12 File

ISA, GS, ST, SE, GE, and IEA segments form the envelope structure of an X12 EDI file. They tell us: Who sent the file Who r...