pynetdicom.pdu_items.PresentationContextItemAC

class pynetdicom.pdu_items.PresentationContextItemAC

A Presentation Context (AC) Ttem.

Presentation Contexts (AC) Items are used by the association acceptor to signal which Abstract Syntaxes and Transfer Syntaxes have been accepted or rejected.

item_length

The number of bytes from the first byte following the Item Length field to the last byte of the Item.

Type

int

item_type

The Item Type field value (0x21).

Type

int

presentation_context_id

The Presentation Context ID field value, an odd integer between 1 and 255.

Type

int or None

result_reason

The Presentation Context’s Result/reason field value.

Type

int

transfer_syntax

The Presentation Context Item’s Transfer Syntax (if available).

Type

list of pydicom.uid.UID

transfer_syntax_sub_item

The Presentation Context Items’ Transfer Syntax Sub-item field value.

Type

list of pynetdicom.uid.UID

Notes

A Presentation Context (AC) Item requires the following parameters:

• Item type (1, fixed value, 0x21)

• Item length (1)

• Presentation context ID (1)

• Result/reason (1)

• Transfer Syntax Sub-item (1)

  • Item type (1, fixed, 0x40)

  • Item length (1)

  • Transfer syntax name (1)

Encoding

When encoded, a Presentation Context (AC) Item has the following structure, taken from Table 9-13 1 (offsets shown with Python indexing). Items are always encoded using Big Endian 2.

Offset	Length	Description
0	1	Item type
1	1	Reserved
2	2	Item length
4	1	Presentation context ID
5	1	Reserved
6	1	Result/reason
7	1	Reserved
8	Variable	Transfer syntax sub-item

References

1

DICOM Standard, Part 8, Section 9.3.3.2

2

DICOM Standard, Part 8, Section 9.3.1

__init__()

Initialise a new Presentation Context (AC) Item.

Methods

__init__()	Initialise a new Presentation Context (AC) Item.
decode(bytestream)	Decode bytestream and use the result to set the field values of the PDU item.
encode()	Return the encoded PDU as bytes.
from_primitive(primitive)	Set the item's values using a Presentation Context primitive.
to_primitive()	Return a PresentationContext primitive from the current Item.

Attributes

context_id	Return the item's Presentation Context ID field value.
item_length	Return the item's Item Length field value as an int.
item_type	Return the item's Item Type field value as an int.
result	Return the item's Result/reason field value.
result_str	Get a string describing the result.
transfer_syntax	Return the Transfer Syntax, if available.