User Manual

SARA-R4/N4 series-AT Commands Manual
UBX-17003787 - R11
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Preface
Page 4 of 308
- No: the current command setting is volatile and cannot be saved
o Can be aborted
- Yes: the command execution can be aborted if a character is sent to the DCE during the command
execution
- No: the command cannot be aborted during the command execution
o Response time: estimated maximum time to get the final result code for the AT command execution.
More precisely, the command response time measures the time from the complete acquisition of the
command line to the issuing of the command result code. This kind of response time is generally lower
than the time measured by the application on the DTE, because the issuing of the command on the
DTE is influenced by the AT interface characteristics (e.g. the synchronous/asynchronous transfer type,
the selected baudrate, etc.), by power saving and flow control, which introduce a variable latency in the
command acquisition by the DCE.
For example, the maximum expected response time shall be extended if the communication with the
module is carried out on a MUX virtual port, because in this case the command line and the result code
are transferred via a specific protocol running on the physical port, that might introduce additional
communication delay due to framing and retransmissions.
Similarly, the maximum expected response time of AT commands accessing the SIM shall be extended
if the module is using a remote SIM card via SAP instead of the local SIM card.
If the response time for a command is left blank (actually "-"), it is an "immediate" response. It means
that the command is executed without asynchronous requests to the protocol stack or the internal
applications, which usually require time to be answered: the command execution is synchronous
(implying that no long blocking processing is done) and lasts a negligible time (the command response
is issued by the module in typically less than 10 ms, and in any case less than 1 s).
The response time shall be extended if the issued AT command triggers a service that cannot be served
immediately due to concurrent access to the same service or resource via AT commands issued on a
different communication port or from internal applications; typical examples are registration commands
and SIM access, that can be also autonomously triggered by the module (e.g. auto-COPS) and can
therefore postpone the execution of the AT commands issued by the user.
o Error reference: reference to the error result codes listed in the Appendix A
u-blox Technical Documentation
As part of our commitment to customer support, u-blox maintains an extensive volume of technical
documentation for our products. In addition to our product-specific technical data sheets, the following
manuals are available to assist u-blox customers in product design and development.
AT Commands Manual: This document provides the description of the AT commands supported by u-blox
cellular modules.
System Integration Manual: This document describes u-blox cellular modules from the hardware and the
software point of view. It provides hardware design guidelines for the optimal integration of the cellular module
in the application device and it provides information on how to set up production and final product tests on
application devices integrating the cellular module.
Application Notes: These documents provide guidelines and information on specific u-blox cellular module
hardware or software topics. See Related documents for application notes related to your cellular module.
Questions
If you have any questions about u-blox Cellular Hardware Integration, please:
• Read this manual carefully
• Contact our information service on our homepage www.u-blox.com
• Read the questions and answers on our FAQ database
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