Introduction To At Commands; At Commands Overview; General System Abbreviations; At Commands Protocol - Fibocom G510 User Manual

2 Introduction to AT Commands

2.1 AT Commands Overview

AT commands are sets of commands used for communication with the cellular modem. AT commands are
comprised of assemblies of ASCII characters which start with the "AT" prefix (except the commands A/
and +++). The AT prefix is derived from the word Attention, which asks the modem to pay attention to the
current request (command).
AT commands are used to request services from the cellular modem, such as:
 Call services: dial, answer and hang up
Cellular utilities: send/receive SMS

 Modem profiles: Auto Answer
 Cellular Network queries: GSM signal quality

2.2 General System Abbreviations

The basic system configuration contains a modem and a terminal.
The G5xx/G6xx is the modem and may be referred to as the DCE or TA, such as the phone, the mobile or
the radio.
The terminal (PC or MCU) may be referred to as the DTE or the TE.

2.3 AT Commands Protocol

The AT commands interface is basically a Modem Services upon Request.Communication (almost)
always begins from the TE side. This means that any service should be requested from the TE. Thus a
request is called a "Command".
Each command must be answered by a "Results code" from the TA. The results code reports the
command status to the TE. Some commands may include several "Results code" to send data back to the
TE. Some commands may initiate a mode in which, when specified events are generated in the
G5xx/G6xx, "Indicator" messages are sent data asynchronously. The "indicators" can be called
"Unsolicited results code".
The G5xx/G6xx can echo characters received from the TE (commands) back to the TE.
G5/G6-Family AT Commands User Manual
TE
Command
Results code
TA (G5xx/G6xx)
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