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execution command as well as all of the subparameter value string).
If all other relevant criteria are met (e.g., the modem is in the proper state), the
command is executed with any indicated subparameters. If <name> is not recognized,
the modem issues the ERROR result code and terminates processing of the command
line. An ERROR is also generated if a subparameter is specified for an action that does
not accept subparameters, if too many subparameters are specified, if a mandatory
subparameter is not specified, if a value is specified of the wrong type, or if a value is
specified that is not within the supported range.
2.4.3.2 Action Test Command Syntax
The DTE may test if an action command is implemented in the modem by using the
syntax:
+<name>=?
If the modem does not recognize the indicated name, it returns an ERROR result code
and terminates processing of the command line. If the modem does recognize the action
name, it returns an OK result code. If the named action accepts one or more
subparameters, the modem sends an information text response to the DTE, prior to the
OK result code, specifying the values supported by the modem for each such
subparameter, and possibly additional information. The format of this information text is
defined for each action command.
2.4.4 Parameter Commands
2.4.4.1 Parameter Types
Parameters may be defined as "read-only" or "read-write". "Read-only" parameters are
used to provide status or identifying information to the DTE, but cannot be set by the
DTE; attempting to set their value is an error. In some cases (specified in the description
of the individual parameter), the modem may ignore attempts to set the value of such
parameters rather than respond with an ERROR result code, if the continued correct
operation of the interface between the modem and DTE will not be affected by such
action. Read-only parameters may be read and tested.
"Read-write" parameters may be set by the DTE, to store a value or values for later use.
Read-write parameters may be set, read, and tested.
Parameters may take either a single value, or multiple (compound) values. Each value
may be either numeric or string; the definition of the parameter will specify the type of
value for each subparameter. Attempting to store a string value in a numeric parameter,
or a numeric value in a string parameter, is an error.
2.4.4.2 Parameter Set Command Syntax
The definition of the parameter indicates, for each value, whether the specification of
that value is mandatory or optional. For optional values, the definition indicates the
assumed (default) value if none is specified; the assumed value may be either a
previous value (i.e., the value of an omitted subparameter retains its previous value), or
a fixed value (e.g., the value of an omitted subparameter is assumed to be zero).
Generally, the default value for numeric parameters is 0, and the default value for string
parameters is "" (empty string).
The following syntax is used for parameters that accept a single value:
+<name>=[<value>]
The following syntax is used for parameters that accept more than one value:
+<name>=[<compound_value>]
For each implemented parameter, if all mandatory values are specified, and all values
are valid according to the definition of the parameter, the specified values are stored. If
<name> is not recognized, one or more mandatory values are omitted, or one or more
values are of the wrong type or outside the permitted range, the modem issues the
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