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Chapter 10 - Voice Mode Operation
10-11
AT Command Syntax
AT is the command line prefix. Voice commands take one of the following forms:
Command-Form Syntax Command-Form Function
+V<CM>? Read current setting.
+V<CM>=? Read permissible settings.
+V<CM>=<string> Set single-value parameter.
+V<CM>=<value_string> Set compound parameter.
Voice AT commands begin with ‘AT’ followed by a ‘+V’ command prefix.
<CM> represents the command character/s. The command parameters can are
made up of <value> and/or <value_string> parameter types. The <value_string>
type consists of multiple values separated by commas or semicolons.
The first two command-forms are for read actions, the last two are for write
actions. A command line may contain either or both action types or be of the read
or write type only.
Response Syntax
For each command line received, the modem issues a response to each command
in the command line followed by a final response.
Each command response is of the form:
<CR><LF>
<value>(or) <value range> (for ? or =? read commands)
<CR><LF>
with a final response of:
<CR><LF>
OK (or) ERROR
<CR><LF>
The final response is OK if all the commands in the command line have been
successfully executed, otherwise it is ERROR.
Note: <CR><LF> characters will not be shown in further examples.
Flow Control
Flow Control is necessary to match the DTE-DCE data rate to the line signaling
rate and to the analog conversion of the voice signals and data. For the Omni
288S, both software XON/XOFF and hardware RTS/CTS flow control are used -
the software flow control is the default setting. The DTE turns off the flow
control, but some other method may be used to avoid overrun of the buffer.