| Segment | Ebene | Beschreibung | Opt/Mand. |
|---|
| UIH | 0 | A service segment starting and uniquely identifying a message. The message type code for the Schedule request - interactive message is SKDREQ. Note: Schedule request - interactive messages conforming to this document must contain the following data in segment UIH, composite S306: Data element 0065 SKDREQ D A UN | Mandatory |
| MSD | 0 | A segment to specify the type and business function of the message. | Mandatory |
| ORG | 0 | A segment to specify details related to the originator of the schedule update | Mandatory |
| HDR | 0 | A segment to specify information applicable to the entire message. | Optional |
| POP | 0 | A segment to specify a period of operation of the service. | Optional |
| ODI | 0 | A segment to specify the origin and destination locations of a service leg or segment. | Optional |
| SG1 | 0 | SG1 | Optional |
| RFR | 1 | A segment to specify a reference to one of the elements of the selection criteria. | Mandatory |
| LKP | 1 | A segment to specify the hierarchical order of the occurrence of the segment group. | Optional |
| SG2 | 0 | SG2 | Optional |
| ERI | 1 | A segment to specify the type of application error | Mandatory |
| RFR | 1 | A segment to reference the erroneous element. | Optional |
| IFT | 1 | A segment to provide text related to the error. | Optional |
| UIT | 0 | A service segment ending a message, giving the total number of segments in the message (including the UIH & UIT) and the control reference number of the message. | Mandatory |
