SimCom SIM7500 Series Installation instructions

SIM7500_SIM7600_SIM7800
Series_MQTT_AT Command Manual_V1.00
Shanghai SIMCom Wireless Solutions Ltd.
Building A, SIM Technology Building, No.633, Jinzhong Road
Changning District 200335
Tel:[phone]
[e-mail]
www.simcom.com
LTE Module

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Document Title: SIM7500_SIM7600_SIM7800
Series_MQTT_AT Command
Manual
Version: 1.00
Date: 2018-10-12
Status: Release
Document ID:
SIM7500_SIM7600_SIM7800 Series_MQTT_AT Command
Manual_V1.00
General Notes
SIMCom offers this information as a service to its customers, to support application and engineering efforts that
use the products designed by SIMCom. The information provided is based upon requirements specifically
provided to SIMCom by the customers. SIMCom has not undertaken any independent search for additional
relevant information, including any information that may be in the customer’s possession. Furthermore, system
validation of this product designed by SIMCom within a larger electronic system remains the responsibility of the
customer or the customer’s system integrator. All specifications supplied herein are subject to change.
Copyright
This document contains proprietary technical information which is the property of SIMCom Limited., copying of
this document and giving it to others and the using or communication of the contents thereof, are forbidden
without express authority. Offenders are liable to the payment of damages. All rights reserved in the event of grant
of a patent or the registration of a utility model or design. All specification supplied herein are subject to change
without notice at any time.
Copyright © Shanghai SIMCom Wireless Solutions Ltd. 2018

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Version History
Version Date Chapter What is new
V1.00 2018-09-28 New version

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Contents
Version History.................................................................................................................................. 2
Contents ............................................................................................................................................ 3
1Introduction................................................................................................................................ 4
1.1 The SSL Context Management AT Commands (for SSL/TLS MQTT)..................................................4
1.2 The process of Using MQTT AT Commands .....................................................................................4
2 Description of AT Command ........................................................................................................... 5
2.1 SSL Context Management AT (only for SSL/TLS MQTT)..................................................................5
2.1.1 AT+CSSLCFG Configure the SSL Context...........................................................................5
2.1.2 AT+CCERTDOWN Download certificate into the module .....................................................9
2.1.3 AT+CCERTLIST List certificates ........................................................................................9
2.1.4 AT+CCERTDELE Delete certificates.................................................................................10
2.2 MQTT Services AT.......................................................................................................................11
2.2.1 AT+CMQTTSTART Start MQTT service ...........................................................................11
2.2.2 AT+CMQTTSTOP Stop MQTT service..............................................................................11
2.2.3 AT+CMQTTACCQ Acquire a client ..................................................................................12
2.2.4 AT+CMQTTREL Release a client......................................................................................13
2.2.5 AT+CMQTTSSLCFG Set the SSL context (only for SSL/TLS MQTT) .................................13
2.2.6 AT+CMQTTWILLTOPIC Input the topic of will message....................................................14
2.2.7 AT+CMQTTWILLMSG Input the will message..................................................................15
2.2.8 AT+CMQTTCONNECT Connect to MQTT server..............................................................16
2.2.9 AT+CMQTTDISC Disconnect from server .........................................................................17
2.2.10 AT+CMQTTTOPIC Input the topic of publish message......................................................18
2.2.11 AT+CMQTTPAYLOAD Input the publish message ...........................................................19
2.2.12 AT+CMQTTPUB Publish a message to server ..................................................................20
2.2.13 AT+CMQTTSUBTOPIC Input the topic of subscribe message............................................21
2.2.14 AT+CMQTTSUB Subscribe a message to server ...............................................................22
2.2.15 AT+CMQTTUNSUBTOPIC Input the topic of unsubscribe message...................................23
2.2.16 AT+CMQTTUNSUB Unsubscribe a message to server ......................................................24
2.2.17 AT+CMQTTCFG Configure the MQTT Context ...............................................................25
2.3 Command result codes and unsolicited codes ..................................................................................26
2.3.1 Command result <err> codes ...............................................................................................26
2.3.2 Unsolicited result codes.......................................................................................................27
3 Example........................................................................................................................................ 29
3.1 Access to MQTT server not SSL/TLS.............................................................................................30
3.2 Connect to SSL/TLS MQTT server (not verify server) .....................................................................32
3.3 Access to SSL/TLS MQTT server (only verify the server) ................................................................34
3.4 Access to SSL/TLS MQTT server (verify server and client)..............................................................36
3.5 Access to MQTT server without checking UTF8 coding ...................................................................39

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This document is a reference guide to all the AT commands defined for MQTT. Through these MQTT AT
commands, you can communicate with a MQTT server.
1Introduction
1.1 The SSL Context Management AT Commands (for SSL/TLS MQTT)
Step 1: Configure SSL version by AT+CSSLCFG=“sslversion”,<ssl_ctx_index>,<sslversion>.
Step 2: Configure SSL authentication mode by AT+CSSLCFG=“authmode”,<ssl_ctx_index>, <authmode>.
Step 3: Configure the flag of ignore local time by
AT+CSSLCFG=“ignorlocaltime”,<ssl_ctx_index>,<ignoreltime>.
Step 4: Configure the max time in SSL negotiation stage by
AT+CSSLCFG=“negotiatetime”,<ssl_ctx_index>,<negotiatetime>.
Step 5: Configure the server root CA by AT+CSSLCFG=“cacert”,<ssl_ctx_index>,<ca_file>.
Step 6: Configure the client certificate by AT+CSSLCFG=“clientcert”,<ssl_ctx_index>,<clientcert_file>.
Step 7: Configure the client key by AT+CSSLCFG=“clientkey”,<ssl_ctx_index>,<clientkey_file>.
Step 8: Download the certificate into the module by AT+CCERTDOWN.
Step 9: Delete the certificate from the module by AT+CCERTDELE.
Step 10: List the certificates by AT+CCERTLIST.
1.2 The process of Using MQTT AT Commands
Step 1: Ensure GPRS network is available before performing SSL related operations.
Step 2: Configure the parameter of PDP context by AT+CGDCONT.
Step 3: Activate the PDP context to start MQTT service by AT+CMQTTSTART.
Step 4: Acquire a client by AT+CMQTTACCQ.
Step 5: Configure SSL context by AT+CSSLCFG (if connect to SSL/TLS MQTT server).
Step 6: Set the SSL context used in SSL connection by AT+CMQTTSSLCFG (if connect to SSL/TLS MQTT
server).
Step 7: Connect to MQTT server by AT+CMQTTCONNECT.
Step 8: Subscribe to message by AT+CMQTTSUB.

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Step 9: Unsubscribe to message by AT+CMQTTUNSUB.
Step 10: Input the topic of a publish message by AT+CMQTTTOPIC.
Step 11: Input the payload of a publish message by AT+CMQTTPAYLOAD.
Step 12: Publish message by AT+CMQTTPUB.
Step 13:Disconnect from the server by AT+CMQTTDISC.
Step 13: Release the client by AT+CMQTTREL.
Step 14: Deactivate the PDP context to stop MQTT service by AT+CMQTTSTOP.
2 Description of AT Command
2.1 SSL Context Management AT (only for SSL/TLS MQTT)
2.1.1 AT+CSSLCFG Configure the SSL Context
AT+CSSLCFG Configure the SSL Context
Test Command
AT+CSSLCFG=?
Response
+CSSLCFG: "sslversion",(0-9),(0-4)
+CSSLCFG: "authmode",(0-9),(0-3)
+CSSLCFG: "ignorelocaltime",(0-9),(0,1)
+CSSLCFG: "negotiatetime",(0-9),(10-300)
+CSSLCFG: "cacert",(0-9),(5-128)
+CSSLCFG: "clientcert",(0-9),(5-128)
+CSSLCFG: "clientkey",(0-9),(5-128)
OK
Read Command
AT+CSSLCFG?
Response
+CSSLCFG:
0,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
1,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
2,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
3,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<

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ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
4,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
5,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
6,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
7,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
8,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
9,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
OK
Write Command
/*Query the configuration of the specified
SSL context*/
AT+CSSLCFG=<ssl_ctx_index>
Response
+CSSLCFG:
<ssl_ctxindex>,<sslversion>,<authmode>,<ignoreltime>,<ne
gotiatetime>,<ca_file>,<clientcert_file>,<clientkey_file>
OK
Write Command
/*Configure the version of the specified SSL
context*/
AT+CSSLCFG="sslversion",<ssl_ctx_in
dex>,<sslversion>
Response
a)If successfully:
OK
b)If failed:
ERROR
Write Command
/*Configure the authentication mode of the
specified SSL context*/
AT+CSSLCFG="authmode",<ssl_ctx_in
dex>,<authmode>
Response
a)If successfully:
OK
b)If failed:
ERROR
Write Command
/*Configure the ignore local time flag of the
specified SSL context*/
AT+CSSLCFG="ignorelocaltime",<ssl_c
tx_index>,<ignoreltime>
Response
a)If successfully:
OK
b)If failed:
ERROR
Write Command Response

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/*Configure the negotiate timeout value of the
specified SSL context*/
AT+CSSLCFG="negotiatetime",<ssl_ctx
_index>,<negotiatetime>
a)If successfully:
OK
b)If failed:
ERROR
Write Command
/*
Configure the server root CA of the
specified SSL context*/
AT+CSSLCFG="cacert",<ssl_ctx_index>
,<ca_file>
Response
a)If successfully:
OK
b)If failed:
ERROR
Write Command
/*
Configure the client certificate of the
specified SSL context*/
AT+CSSLCFG="clientcert",<ssl_ctx_ind
ex>,<clientcert_file>
Response
a)If successfully:
OK
b)If failed:
ERROR
Write Command
/*
Configure the client key of the specified
SSL context*/
AT+CSSLCFG="clientkey",<ssl_ctx_ind
ex>,<clientkey_file>
Response
a)If successfully:
OK
b)If failed:
ERROR
Defined Values
<ssl_ctx_index> The SSL context ID. The range is 0-9.
<sslversion> The SSL version, the default value is 4.
0 – SSL3.0
1 – TLS1.0
2 – TLS1.1
3 – TLS1.2
4 – All
The configured version should be support by server. So you
should use the default value if you can’t confirm the version
which the server supported.
<authmode>
The authentication mode, the default value is 0.
0 – no authentication.
1 –server authentication. It needs the root CA of the server.
2 –server and client authentication. It needs the root CA of the
server, the cert and key of the client.
3–client authentication and no server authentication. It needs the
cert and key of the client.
<ignoreltime> The flag to indicate how to deal with expired certificate, the
default value is 1.
0 – care about time check for certification.
1 – ignore time check for certification

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When set the value to 0, it need to set the right current date and
time by AT+CCLK when need SSL certification.
<negotiatetime> The timeout
value used in SSL negotiate stage. The range is
10-300 seconds. The default value is 300.
<ca_file>
The root CA file name of SSL context. The file name must have
type like “.pem” or “.der”.The length of filename is from 5 to
128 bytes.
If the filename contains non-
ASCII characters, the file path
parameter should contain a prefix of {non-
ascii} and the
quotation mark (The string in the quotation mark should be
hexadecimal of the filename’s UTF8 code).
There are two ways to download certificate files to module:
1. By AT+CCERTDOWN.
2. By FTPS or HTTPS commands. Please refer to:
SIM7500_SIM7600_SIM7800 Series_FTPS_AT Command
Manual
and SIM7500_SIM7600_SIM7800 Series_HTTP_AT
Command Manual
<clientcert_file>The client cert file name of SSL context. The file name must
have type like “.pem” or “.der”.The length of filename is from 5
to 128 bytes.
If the filename contains non-
ASCII characters, the file path
parameter should contain a prefix of {non-
ascii} and the
quotation mark (The string in the quotation
mark should be
hexadecimal of the filename’s UTF8 code).
There are two ways to download certificate files to module:
1. By AT+CCERTDOWN.
2. By FTPS or HTTPS commands. Please refer to:
SIM7500_SIM7600_SIM7800 Series_FTPS_AT Command
Manual and SIM7500_SIM7
600_SIM7800 Series_HTTP_AT
Command Manual
<clientkey_file>
The client key file name of SSL context. The file name must
have type like “.pem” or “.der”.The length of filename is from 5
to 128 bytes.
If the filename contains non-ASCII characters, the file path
parameter should contain a prefix of {non-
ascii} and the
quotation mark (The string in the quotation mark should be
hexadecimal of the filename’s UTF8 code).
There are two ways to download certificate files to module:
1. By AT+CCERTDOWN.

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2. By FTPS or HTTPS commands. Please refer to:
SIM7500_SIM7600_SIM7800 Series_FTPS_AT Command
Manual and SIM7500_SIM7600_SIM7800 Series_HTTP_AT
Command Manual
2.1.2 AT+CCERTDOWN Download certificate into the module
AT+CCERTDOWN Download certificate into the module
Test Command
AT+CCERTDOWN=?
Response
+CCERTDOWN: (5-128),(1-10240)
OK
Write Command
AT+CCERTDOWN=<filename>,<len>
Response
a)If it can be download:
>
<input data here>
b)If failed:
ERROR
Defined Values
<filename>
The name of the certificate/key file. The file name must have
type like “.pem” or “.der”. The length of filename is from 5 to
128 bytes.
If the filename contains non-
ASCII characters, the file path
parameter should contain a prefix of {non-
ascii} and the
quotation mark (The string in the
quotation mark should be
hexadecimal of the filename’s UTF8 code).
For example: If you want to download a file with name “中
华.pem”, you should convert the “中华.pem” to UTF8 coding
(&#x4E2D;&#x534E;.pem), then input the hexadecimal
(262378344532443B262378353334453B2E70656D
) of UTF8
coding.
<len> The length of the file data to send. The range is from 1 to 10240
bytes.
2.1.3 AT+CCERTLIST List certificates
AT+CCERTLIST List certificates
Execute Command Response

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AT+CCERTLIST [+CCERTLIST:<file_name>
[+CCERTLIST:<file_name>]
…
<CR><LF>]
OK
Defined Values
<filename>
The certificate/key files which has been downloaded to the
module.
If the filename contains non-ASCII characters, it will show the
non-ASCII characters as UTF8 code.
2.1.4 AT+CCERTDELE Delete certificates
AT+CCERTDELE Delete certificate from the module
Write Command
AT+CCERTDELE=<filename>
Response
a)If delete successfully:
OK
b)If failed:
ERROR
Defined Values
<filename>
The name of the certificate/key file. The file name must have
type like “.pem” or “.der”. The length of filename is from 5 to
128 bytes.
If the filename contains non-
ASCII characters, the file path
parameter should contain a prefix of {non-
ascii} and the
quotation mark (The string in the quotation mark should be
hexadecimal of the filename’s UTF8 code).
For example: If you want to download a file with name “中
华.pem”, you should convert the “中华.pem” to UTF8 coding
(&#x4E2D;&#x534E;.pem), then input the hexadecimal
(262378344532443B262378353334453B2E70656D
) of UTF8
coding.

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2.2 MQTT Services AT
2.2.1 AT+CMQTTSTART Start MQTT service
AT+CMQTTSTART is used to start MQTT service by activating PDP context. You must execute this command
before any other MQTT related operations.
AT+CMQTTSTART Start MQTT service
Execute Command
AT+CMQTTSTART
Response
a)If start MQTT service successfully:
OK
+CMQTTSTART: <err>
b)If start MQTTservice successfully:
+CMQTTSTART: <err>
OK
c)If failed:
ERROR
d)If failed:
ERROR
+CMQTTSTART: <err>
Maximum Response Time 120000ms
Defined Values
<err> The result code, please refer to chapter 2.3.1
2.2.2 AT+CMQTTSTOP Stop MQTT service
AT+CMQTTSTOP is used to stop MQTT service.
AT+CMQTTSTOP STOP MQTT service
Execute Command
AT+CMQTTSTOP
Response
a)If stop MQTT service successfully:
+CMQTTSTOP: <err>
OK
b)If stop MQTT service successfully:

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OK
+CMQTTSTOP: <err>
c)If failed:
ERROR
Defined Values
<err> The result code, please refer to chapter 2.3.1
2.2.3 AT+CMQTTACCQ Acquire a client
AT+CMQTTACCQ is used to acquire a MQTT client. It must be called before all commands about MQTT
connect and after AT+CMQTTSTART.
AT+CMQTTACCQ Acquire a client
Test Command
AT+CMQTTACCQ=?
Response
+CMQTTACCQ: (0-1),(1-23),(0-1)
OK
Read Command
AT+CMQTTACCQ?
Response
+CMQTTACCQ: <client_index>, <clientID>,<server_type>
+CMQTTACCQ: <client_index>, <clientID>,<server_type>
OK
Write Command
AT+CMQTTACCQ=<client_index>,
<clientID>[, <server_type>]
Response
a)If successfully:
OK
b)If failed:
+CMQTTACCQ: <client_index>,<err>
ERROR
c) If failed:
ERROR
Defined Values
<client_index> A
numeric parameter that identifies a client. The range of
permitted values is 0 to 1.
<clientID> The UTF-
encoded string. It specifies a unique identifier for the
client. The string length is from 1 to 23 bytes.
<server_type> A numeric parameter that identifies the server type. The default
value is 0.

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0 - MQTT server with TCP
1-MQTT server with SSL/TLS
<err> The result code, please refer to chapter 2.3.1
2.2.4 AT+CMQTTREL Release a client
AT+CMQTTREL is used to release a MQTT client. It must be called after AT+CMQTTDISC and before
AT+CMQTTSTOP.
AT+CMQTTREL Release a client
Test Command
AT+CMQTTREL=?
Response
+CMQTTREL: (0-1)
OK
Read Command
AT+CMQTTREL?
Response
OK
Write Command
AT+CMQTTREL=<client_index>
Response
a)If successfully:
OK
b)If failed:
+CMQTTREL: <client_index>,<err>
ERROR
c) If failed:
ERROR
Defined Values
<client_index> A
numeric parameter that identifies a client. The range of
permitted values is 0 to 1.
<err>
The result code, please refer to chapter 2.3.1.
2.2.5 AT+CMQTTSSLCFG Set the SSL context (only for SSL/TLS MQTT)
AT+CMQTTSSLCFG is used to set the SSL context which to be used in the SSL connection when it will connect
to a SSL/TLS MQTT server. It must be called before AT+CMQTTCONNECT and after AT+CMQTTSTART.
The setting will be cleared after the CMQTTCONNECT operation is finished.
NOTE: If you don’t set the SSL context by this command before connecting to server by
AT+CMQTTCONNECT, the CMQTTCONNECT operation will use the SSL context as same as index
<session_id> (the 1st parameter of AT+ CMQTTCONNECT) when connecting to the server.

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AT+CCHSSLCFG Set the SSL context
Test Command
AT+CMQTTSSLCFG=?
Response
+ CMQTTSSLCFG: (0,1),(0-9)
OK
Read Command
AT+CMQTTSSLCFG?
Response
+CMQTTSSLCFG: <session_id>,[<ssl_ctx_index >]
+CMQTTSSLCFG: <session_id>,[<ssl_ctx_index >]
OK
Write Command
AT+CMQTTSSLCFG=<session_id>,<ssl
_ctx_index>
Response
a)If successfully:
OK
b)If failed:
ERROR
Defined Values
<session_id> The session_id to operate. It’s from 0 to 1
<ssl_ctx_index>
The SSL context ID which will be used in the SSL connection.
Refer to the <ssl_ctx_index> of AT+CSSLCFG
2.2.6 AT+CMQTTWILLTOPIC Input the topic of will message
AT+CMQTTWILLTOPIC is used to input the topic of will message.
AT+CMQTTWILLTOPIC Input the will topic
Test Command
AT+CMQTTWILLTOPIC=?
Response
+CMQTTWILLTOPIC: (0-1),(1-1024)
OK
Write Command
AT+CMQTTWILLTOPIC=<client_index
>,<req_length>
Response
a)If successfully:
>
<input data here>
OK
b)If failed:
+CMQTTWILLTOPIC: <client_index>,<err>
ERROR
c)If failed:

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ERROR
Defined Values
<client_index> A numeric parameter that identifies a client. The range of permitted
values is 0 to 1.
<req_length>
The length of input topic. The will topic should be UTF-encoded
string. The range is from 1 to 1024 bytes.
<err> The result code, please refer to chapter 2.3.1
2.2.7 AT+CMQTTWILLMSG Input the will message
AT+CMQTTWILLMSG is used to input the message body of will message.
AT+CMQTTWILLTOPIC Input the will message
Test Command
AT+CMQTTWILLMSG=?
Response
+CMQTTWILLMSG: (0-1),(1-10240),(0-2)
OK
Write Command
AT+CMQTTWILLMSG=<client_index>,
<req_length>,<qos>
Response
a)If successfully:
>
<input data here>
OK
b)If failed:
+CMQTTWILLMSG: <client_index>,<err>
ERROR
c)If failed:
ERROR
Defined Values
<client_index> A
numeric parameter that identifies a client. The range of
permitted values is 0 to 1.
<req_length> The length of input data. The will message
should be
UTF-encoded string. The range is from 1 to 10240 bytes.
<qos> The qos value of the will message. The range is from 0 to 2.
<err> The result code: 0 is success. Other values are failure. Please
refer to chapter 2.3.1

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2.2.8 AT+CMQTTCONNECT Connect to MQTT server
AT+CMQTTCONNECT is used to connect to a MQTT server.
NOTE: If you don’t set the SSL context by AT+CMQTTSSLCFG before connecting a SSL/TLS MQTT server by
AT+CMQTTCONNECT, it will use the <client_index> (the 1st parameter of AT+CMQTTCONNNECT) SSL
context when connecting to the server.
AT+CMQTTCONNECT Connect to MQTT server
Test Command
AT+CMQTTCONNECT=?
Response
+CMQTTCONNECT: (0-1),(9-256),(60-64800),(0-1)
OK
Read Command
AT+CMQTTCONNECT?
Response
+CMQTTCONNECT:
0[,<server_addr>,<keepalive_time>,<clean_session>[,<user_
name>[,<pass_word>]]]
+CMQTTCONNECT:
1[,<server_addr>,<keepalive_time>,<clean_session>[,<user_
name>[,<pass_word>]]]
OK
Write Command
AT+CMQTTCONNECT=<client_index>,
<server_addr>,<keepalive_time>,<clean_
session>[,<user_name>[,<pass_word>]]
Response
a)If successfully:
OK
+CMQTTCONNECT: <client_index>,0
b)If failed:
OK
+CMQTTCONNECT: <client_index>,<err>
c)If failed:
+CMQTTCONNECT: <client_index>,<err>
ERROR
d)If failed:
ERROR
Defined Values
<client_index> A
numeric parameter that identifies a client. The range of
permitted values is 0 to 1.
<server_addr> The string that described the server address and port. The range
of the string length is 9 to 256 bytes. The string should be like

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this “tcp://116.247.119.1
65:5141”, must begin with “tcp://”. If
the <server_addr> not include the port, the default port is 1883.
<keepalive_time>
The time interval between two messages received from a client.
The client will send a keep-
alive packet when there is no
message sent to server after song long time. The range is from
60s to 64800s (18 hours).
<clean_session>
The clean session flag. The value range is from 0 to 1, and
default value is 0.
0 -
the server must store the subscriptions of the client after it
disconnected. This includes continuing to store QoS 1 and QoS
2 messages for the subscribed topics so that they can be
delivered when the client reconnects. The server must also
maintain the state of in-
flight messages being delivered at the
point the connection is lost. This information must be kept until
the client reconnects.
1 -
the server must discard any previously maintained
information about the client and treat the connection as "clean".
The server must also discard any state when the client
disconnects.
<user_name>
The user name identifies the name of the user which can be used
for authentication when connecting to server. The string length
is from 1 to 256 bytes.
<password>
The password corresponding to the user which can be used for
authentication when connecting to server
. The string length is
from 1 to 256 bytes.
<err> The result code: 0 is success. Other values are failure. Please
refer to chapter 2.3.1.
2.2.9 AT+CMQTTDISC Disconnect from server
AT + CMQTTDISC is used to disconnect from the server.
AT+CMQTTDISC Disconnect from server
Test Command
AT+CMQTTDISC=?
Response:
+CMQTTDISC: (0-1),(0, 60-180)
OK
Read Command
AT+CMQTTDISC?
Response:
+CMQTTDISC: 0,<disc_state>
+CMQTTDISC: 1,<disc_state>

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OK
Write Command
AT+CMQTTDISC=<client_index>,<time
out>
Response
a)If connect successfully：
+CMQTTDISC: <client_index>,0
OK
b)If connect successfully：
OK
+CMQTTDISC: <client_index>,0
c)
If failed：
OK
+CMQTTDISC: <client_index>,<err>
d)If failed:
ERROR
e)If failed:
+CMQTTDISC: <client_index>,<err>
ERROR
Defined Values
<client_index> A numeric parameter that identifies a client. The range of permitted
values is 0 to 1.
<timeout> The timeout value for disconnection. The unit is second. The range
is 60s to 180s. The default value is 0s (not set the timeout value).
<disc_state> 1 - disconnection
0 - connection
<err> The result code: 0 is success. Other values are failure. Please refer
to chapter 2.3.1.
2.2.10 AT+CMQTTTOPIC Input the topic of publish message
AT+CMQTTTOPIC is used to input the topic of a publish message.
NOTE: The topic will be clean after execute AT+CMQTTPUB.
AT+CMQTTTOPIC Input the publish message topic
Test Command Response
+CMQTTTOPIC: (0-1),(1-1024)

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AT+CMQTTTOPIC=?
OK
Write Command
AT+CMQTTTOPIC=<client_index>,<re
q_length>
Response
a)If successfully:
>
<input data here>
OK
b)If failed:
+CMQTTTOPIC: <client_index>,<err>
ERROR
c)If failed:
ERROR
Defined Values
<client_index> A numeric parameter that identifies a client. The range of permitted
values is 0 to 1.
<req_length> The length of input topic data. The publish message topic should be
UTF-encoded string. The range is from 1 to 1024 bytes.
<err> The result code: 0 is success. Other values are failure. Please refer
to chapter 2.3.1.
2.2.11 AT+CMQTTPAYLOAD Input the publish message
AT+CMQTTPAYLOAD is used to input the message body of a publish message.
NOTE: The payload will be clean after execute AT+CMQTTPUB.
AT+CMQTTPAYLOAD Input the publish message body
Test Command
AT+CMQTTPAYLOAD=?
Response
+CMQTTPAYLOAD: (0-1),(1-10240)
OK
Write Command
AT+CMQTTPAYLOAD=<client_index>,
<req_length>
Response
a)If successfully:
>
<input data here>
OK
b)If failed:
+CMQTTPAYLOAD: <client_index>,<err>
ERROR