Advanced Audio Distribution / Profile Specification
Bluetooth SIG Proprietary Page 12 of 73
• Addition of support for MPEG-D USAC
• Clarification that apart from SBC, the specification contains codec interoperability requirements and
not the codecs themselves
1.5 Language
1.5.1 Language conventions
The Bluetooth SIG has established the following conventions for use of the words shall, must, will,
should, may, can, and note in the development of specifications:
is required to – used to define requirements.
is used to express:
a natural consequence of a previously stated mandatory requirement.
OR
an indisputable statement of fact (one that is always true regardless of the
circumstances).
it is true that – only used in statements of fact.
is recommended that – used to indicate that among several possibilities one
is recommended as particularly suitable, but not required.
is permitted to – used to allow options.
is able to – used to relate statements in a causal manner.
Text that calls attention to a particular point, requirement, or implication or
reminds the reader of a previously mentioned point. It is useful for clarifying
text to which the reader ought to pay special attention. It shall not include
requirements. A note begins with “Note:” and is set off in a separate
paragraph. When interpreting the text, the relevant requirement shall take
precedence over the clarification.
If there is a discrepancy between the information in a figure and the information in other text of the
specification, the text prevails. Figures are visual aids including diagrams, message sequence charts
(MSCs), tables, examples, sample data, and images. When specification content shows one of many
alternatives to satisfy specification requirements, the alternative shown is not intended to limit
implementation options. Other acceptable alternatives to satisfy specification requirements may also be
possible.
1.5.2 Reserved for Future Use
Where a field in a packet, Protocol Data Unit (PDU), or other data structure is described as "Reserved for
Future Use" (irrespective of whether in uppercase or lowercase), the device creating the structure shall
set its value to zero unless otherwise specified. Any device receiving or interpreting the structure shall
ignore that field; in particular, it shall not reject the structure because of the value of the field.
Where a field, parameter, or other variable object can take a range of values, and some values are
described as "Reserved for Future Use," a device sending the object shall not set the object to those
values. A device receiving an object with such a value should reject it, and any data structure containing
it, as being erroneous; however, this does not apply in a context where the object is described as being
ignored or it is specified to ignore unrecognized values.