Telenetics 56 - Manual (Page 38)

AT Commands
Page 30
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.
Parameter Commands
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.
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).