Z02215
Single Chip Modem with Integrated Controller, Data Pump, and AFE
15
Command Line Execution
The characters in a command line are executed one at a time. Any unexpected
characters (except control characters) stop command line execution and return an
ERRORresult code. Unexpected characters include numbers outside the range of
values accepted by the command. All control characters in a command line
except Ctrl-X(and the special characters such as <CR> and <BS>) are ignored.
The numerical argument of a command is assumed to be 0 if it is not provided.
For example, the commands ATH<CR> and ATH0<CR> both hang up the telephone
line.
When the modem has executed a command line, the result code of the most
recent command executed is returned to the terminal.
If the value written to a modem S-register is outside the range of values accepted
by the S-register, then its value is set to the nearest allowed value.
Leading 0s in numeric arguments, including S-register numbers, are ignored. For
example, both set S-register S1 to 2:
ATS1=2
ATS01=2
All numeric arguments, including S-register numbers, are decimal (base 10).
AT Command Prefix
Each modem command line begins with the letters Aand T. The modem uses
these characters to determine the data rate and parity from the terminal.
A/ Repeat Last Command
To repeat the commands in the most recent command line, type the letters Aand /
instead of Aand T.
<CR> End-of-Line Character
This character is typed to end a command line. The value of the <CR> character is
stored in S-register S3. The default value is 13(the ASCII carriage return charac-
ter).
When the <CR> character is entered, the modem executes the commands in the
command line.
PS001907-0904
AT Command Set
ZILOG [ ZILOG, INC. ]
