LTE Module Series
EC25&EC21 AT Commands Manual
EC25&EC21_AT_Commands_Manual 9 / 231
1 Introduction
1.1. Scope of the Document
This document presents the AT Commands Set for Quectel cellular engines EC25 & EC21.
1.2. AT Command Syntax
The “AT” or “at” prefix must be set at the beginning of each command line. To terminate a command line
enter <CR>. Commands are usually followed by a response that includes
“<CR><LF><response><CR><LF>”. Throughout this document, only the responses are presented,
“<CR><LF>” are omitted intentionally.
The AT Commands Set implemented by EC25 & EC21 is a combination of 3GPP TS 27.007, 3GPP TS
27.005 and ITU-T recommendation V.25ter as well as the AT Commands developed by Quectel.
All these AT commands can be split into three categories syntactically: “basic”, “S parameter”, and
“extended”. They are listed as follows:
Basic syntax
These AT commands have the format of “AT<x><n>”, or “AT&<x><n>”, where “<x>” is the command, and
“<n>” is/are the argument(s) for that command. An example of this is “ATE<n>”, which tells the DCE
whether received characters should be echoed back to the DTE according to the value of “<n>”. “<n>” is
optional and a default will be used if it is missing.
S parameter syntax
These AT commands have the format of “ATS<n>=<m>”, where “<n>” is the index of the S register to set,
and “<m>” is the value to assign to it.
Extended syntax
These commands can be operated in several modes, as following table: