Comtrol AT Commands - Manual (Page 22)

AT Commands for CX81801/CX06833/CX81300/CX06827 Modems Reference Manual
Conexant 102184B
2-8
The semicolon is not necessary when the extended syntax command is the last command
on the command line.
Concatenating Commands after Basic Format Commands
Extended syntax commands may appear on the same command line after a basic syntax
command without a separator, in the same manner as concatenation of basic syntax
commands.
2.5 Issuing Commands
All characters in a command line must be issued at the same data rate, and with the
same parity and format.
The modem will ignore any command line that is not properly terminated. The modem
may consider 30 seconds of mark idle time between any two characters as an improperly
terminated command line. In this case the modem may or may not generate an ERROR
message. The modem will ignore any characters received from the DTE that are not part
of a properly-formatted command line.
If the maximum number of characters that the modem can accept in the body is exceeded,
an ERROR result code is generated after the command line is terminated.
The DTE will not begin issuing a subsequent command line until at least one-tenth of a
second has elapsed after receipt of the entire result code issued by the modem in response
to the preceding command line.
2.6 Executing Commands
Upon receipt of the termination character, the modem commences execution of the
commands in the command line in the order received from the DTE. Should execution of
a command result in an error, or a character be not recognized as a valid command,
execution is terminated, the remainder of the command line is ignored, and the ERROR
result code is issued. Otherwise, if all commands execute correctly, only the result code
associated with the last command is issued; result codes for preceding commands are
suppressed. If no commands appear in the command line, the OK result code is issued.
2.6.1 Aborting Commands
Some action commands that require time to execute may be aborted while in progress;
these are explicitly noted in the description of the command. Aborting of commands is
accomplished by the transmission from the DTE to the modem of any character. A single
character is sufficient to abort the command in progress; however, characters transmitted
during the first 125 milliseconds after transmission of the termination character are
ignored (to allow for the DTE to append additional control characters such as line feed
after the command line termination character). To ensure that the aborting character is
recognized by the modem, it should be sent at the same rate as the preceding
command line; the modem may ignore characters sent at other rates. When such an
aborting event is recognized by the modem, the modem terminates the command in
progress and returns an appropriate result code to the DTE, as specified for the particular
command.