Comtrol AT Commands for SmartACFL - Manual (Page 18)

Command Reference Manual
2-6 Conexant 100722A
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.
2.6.2 Handling of Invalid Numbers and S-Parameter Values
The modem reacts to undefined numbers and S-parameter values in one of three ways:
1. Issue the ERROR result code, and leave the previous value of the parameter unchanged;
2. Issue the OK result code, and leave the previous value of the parameter unchanged; or,
3. Issue the OK result code, and set the parameter value to the valid value nearest to that specified in the command line.
The description of each command specifies which of these three techniques is used to handle invalid parameter values for
that command or parameter.
2.7 Modem Responses
While in command state and online command state, the modem will issue responses using the same rate, word length, and
parity as the most recently received DTE command line. In the event that no DTE command has yet been received, rate, word
length, and parity used will depend on the capabilities of the modem.
When the modem transitions from the command state or online command state to the online data state, the result code
CONNECT should be issued at the bit rate and parity used during the command state. When the modem transitions from the
online data state to the command state or online command state, the result codes should be issued at the bit rate used during
the online data state. Thereafter, any unsolicited result codes should use the bit rate and parity of the last command line
issued by the DTE to the modem.
The characters of a response will be contiguous, with no more than 100 milliseconds of mark idle issued between characters
in addition to stop elements.