Product data

USRobotics
Command Reference
Syntax and Procedures - 3
Syntax and Procedures
The command and response syntax and procedures generally conform to
referenced recommendations and standards. Since these recommendations and
standards describe characteristics universal to a large installed base of modems
to a maximum degree, there may be syntax and procedural differences due to
extensions and behavioral differences in implemented commands, parameters,
and responses beyond that described in these recommendations and standards.
The syntax and procedures described in this section are based on V.250 and
V.253 with additional information included for implemented extensions, behavioral
differences beyond V.250, and legacy commands.
Alphabet
The T.50 International Alphabet 5 (IA5) is used in this document. Only the low-
order seven bits of each character are significant to the modem; any eighth or
higher-order bit(s), if present, are ignored for the purpose of identifying commands
and parameters. Lower-case characters are considered identical to their upper-
case equivalents when received by the modem from the DTE. Result codes from
the modem are in upper case.
DTE Commands Lines
Words enclosed in <angle brackets> are references to syntactical elements. The
brackets are not used when the words appear in a command line. Words enclosed
in [square brackets] represent optional items which may be omitted from the
command line at the specified point. The square brackets are not used when the
words appear in the command line. Other characters that appear in syntax
descriptions must as included as shown.
Any modem responses are mentioned in terms of their alphabetic format; the
actual response issued will depend on the setting of parameters that affect
response formats, e.g., Q and V commands.
Command Line General Format
A command line is made up of three elements: the prefix, the body, and the
termination character.
The command line prefix consists of the characters "AT" or "at" or, to repeat the
execution of the previous command line, the characters "A/" or "a/".
The body is made up of individual commands described in this document. Space
characters (IA5 2/0) are ignored and may be used freely for formatting purposes,
unless they are embedded in numeric or string constants. The termination