The Presentation Context Item shall be made of a sequence of mandatory fixed length fields followed by a variable field. Table 9-18 shows the sequence of the mandatory fields.
The variable field shall consist of one Transfer Syntax Sub-Item.
Table 9-18. Presentation Context Item Fields
|
Item bytes |
Field name |
Description of field |
|---|---|---|
|
1 |
Item-type |
21H |
|
2 |
Reserved |
This reserved field shall be sent with a value 00H but not tested to this value when received. |
|
3-4 |
Item-length |
This Item-length shall be the number of bytes from the first byte of the following field to the last byte of the Transfer Syntax Sub-Item. It shall be encoded as an unsigned binary number. |
|
5 |
Presentation-context-ID |
Presentation-context-ID values shall be odd integers between 1 and 255, encoded as an unsigned binary number. For a complete description of the use of this field see Section 7.1.1.13. |
|
6 |
Reserved |
This reserved field shall be sent with a value 00H but not tested to this value when received. |
|
7 |
Result/Reason |
This Result/Reason field shall contain an integer value encoded as an unsigned binary number. One of the following values shall be used: 0 - acceptance 1 - user-rejection 2 - no-reason (provider rejection) 3 - abstract-syntax-not-supported (provider rejection) 4 - transfer-syntaxes-not-supported (provider rejection) |
|
8 |
Reserved |
This reserved field shall be sent with a value 00H but not tested to this value when received. |
|
9-xxx |
Transfer syntax sub-item |
This variable field shall contain one Transfer Syntax Sub-Item. When the Result/Reason field has a value other than acceptance (0), this field shall not be significant and its value shall not be tested when received. For a complete description of the use and encoding of this item see Section 9.3.3.2.1. |
The Transfer Syntax Sub-Item shall be made of a sequence of mandatory fixed length fields followed by a variable field. Table 9-19 shows the sequence of the mandatory fields.
Table 9-19. Transfer Syntax Sub-Item Fields
|
Item bytes |
Field name |
Description of field |
|---|---|---|
|
1 |
Item-type |
40H |
|
2 |
Reserved |
This reserved field shall be sent with a value 00H but not tested to this value when received. |
|
3-4 |
Item-length |
This Item-length shall be the number of bytes from the first byte of the following field to the last byte of the Transfer-syntax-name field. It shall be encoded as an unsigned binary number. |
|
5-xxx |
Transfer-syntax-name |
This variable field shall contain the Transfer-syntax-name proposed for this presentation context. A valid Transfer-syntax-name shall be encoded as defined in Annex F. For a description of the use of this field see Section 7.1.1.14. Transfer-syntax-names are structured as UIDs as defined in PS3.5 (see Annex B for an overview of this concept). DICOM Transfer-syntax-names are registered in PS3.5. |