Comtrol AT Commands - Manual (Page 17)

AT Commands for CX81801/CX06833/CX81300/CX06827 Modems Reference Manual
102184B Conexant 2-3
where <command> is either a single character, or the "&" character followed by a single
character per V.250. In addition, <command> can be the "%" character followed by a
single character, the "*" character followed by a single character, or the "^" character
followed by a single character.
<number> may be a string of one or more characters from "0" through "9" representing a
decimal integer value. Commands that expect a <number> are noted in the description of
the command. If a command expects <number> and it is missing (<command> is
immediately followed in the command line by another <command> or the termination
character), the value "0" is assumed. If a command does not expect a <number> and a
number is present, an ERROR is generated. All leading "0"s in <number> are ignored by
the modem.
Additional commands may follow a command (and associated parameter, if any) on the
same command line without any character required for separation. The actions of some
commands cause the remainder of the command line to be ignored (e.g., A).
See the D command for details on the format of the information that follows it.
2.3.2 S-Parameters
Commands that begin with the letter "S" are known as "S-parameters". The number
following the "S" indicates the "parameter number" being referenced. If the number is not
recognized as a valid parameter number, an ERROR result code is issued.
Immediately following this number, either a "?" or "=" character must appear. "?" is used
to read the current value of the indicated S-parameter; "=" is used to set the S-parameter
to a new value.
S<parameter_number>?
S<parameter_number>=[<value>]
If the "=" is used, the new value to be stored in the S-parameter is specified in decimal
following the "=". If no value is given (i.e., the end of the command line occurs or the
next command follows immediately), the S-parameter specified may be set to 0, or an
ERROR result code issued and the stored value left unchanged. The ranges of acceptable
values are given in the description of each S-parameter.
If the "?" is used, the modem transmits a single line of information text to the DTE. The
text portion of this information text consists of exactly three characters, giving the value
of the S-parameter in decimal, with leading zeroes included.