Command line editing, Command line echo, Repeating a command line – Comtrol AT Commands User Manual

Page 16: Types of dte commands, Basic syntax commands, Basic syntax command format, 3 basic syntax commands

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AT Commands for CX81801/CX06833/CX81300/CX06827 Modems Reference Manual

Conexant

102184B

2-2

2.2.2

Command Line Editing

The character defined by parameter S5 (default, BS) is interpreted as a request from the
DTE to the modem to delete the previous character. Any control characters (IA5 0/0
through 1/15, inclusive) that remain in the command line after receipt of the termination
character are ignored by the modem.

The modem checks characters from the DTE first to see if they match the termination
character (S3), then the editing character (S5), before checking for other characters. This
ensures that these characters will be properly recognized even if they are set to values
that the modem uses for other purposes. If S3 and S5 are set to the same value, a
matching character will be treated as matching S3 (S3 is checked before S5).

2.2.3

Command Line Echo

The modem may echo characters received from the DTE during command state and
online command state back to the DTE, depending on the setting of the E command. If
enabled, characters received from the DTE are echoed in the same format as received.
Invalid characters in the command line or incomplete or improperly-formed command
line prefixes may not be echoed.

2.2.4

Repeating a Command Line

If the prefix "A/" or "a/" is received, the modem immediately executes once again the
body of the preceding command line. No editing is possible, and no termination character
is necessary. A command line may be repeated multiple times in this manner. Responses
to the repeated command line are issued using format of the original command line. If
"A/" is received before any command line has been executed, the preceding command
line is assumed to have been empty (that results in an OK result code).

2.2.5

Types of DTE Commands

There are two types of commands: action commands and parameter commands.
Commands of either type may be included in command lines, in any order.

Action commands may be "executed" (to invoke a particular function of the equipment,
which generally involves more than the simple storage of a value for later use), or
"tested" (to determine whether or not the equipment implements the action command,
and, if subparameters are associated with the action, the ranges of subparameter values
that are supported).

Parameters may be "set" (to store a value or values for later use), "read" (to determine the
current value or values stored), or "tested" (to determine whether or not the equipment
implements the parameter, and the ranges of values supported).

2.3

Basic Syntax Commands

2.3.1

Basic Syntax Command Format

The format of Basic Syntax commands, except for the D and S commands, is as follows:

<command>[<number>]

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