Understanding The Command Format - Polycom SoundStructure C16 Design Manual

as strings, their values are a sequence in a pre-defined order. Thus, they can be incremented and
decremented. When incremented or decremented beyond their range, they wrap around to the beginning
or end of the list, respectively.

Understanding the Command Format

Referring to the command hierarchy below, each sub-category of command inherits the syntax of its parent
and adds further syntax requirements. Starting at the root of the hierarchy, all commands have the following
syntax:
<action> <data> <term>
where <action> specifies the system-defined action, <data> is the action-specific arguments or payload
data, and <term> is the command terminator.
Actions
The <action> field, also known as the command action, consists only of lowercase characters. The full set
of actions is provided later in this chapter.
Data
The content and format of the command data is specific to the command action. The SoundStructure
control protocol defines three primary groups of actions: channel definition actions, parameter control
actions, and data transfer actions. Details on specific command actions are given in later sections.
Command Termination
Commands sent to SoundStructure must be terminated by either a single carriage return (000D) or a
carriage return followed by a line feed (000A). The single carriage return is the preferred method of
command termination; however both formats will be supported in order to provide a protocol that is robust
to differing line end conventions.
Commands (for example, acknowledgments) generated by SoundStructure will always be terminated with
a single carriage return (000D).
Note: Lowercase SoundStructure Commands
All commands for SoundStructure must be lowercase and terminated with a single
carriage return (000D) or a carriage return (000D) followed by a line feed (000A).
Command Acknowledgments
All commands generate acknowledgments. The format of the acknowledgment and whether it is sent to the
originating interface or all interfaces depends on the specific command. In general, the acknowledgment is
similar to the command that caused it.
The acknowledgment is sent to all interfaces if a setting changed. The acknowledgment is only sent to the
originating interface if no settings changed, for example, a query for a parameter is made.
Command Length
All commands must be less than or equal to 2048 bytes in length, including the terminator.
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