SimCom SIM7800 Series User Manual

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SIM7500_SIM7600_SIM7800 Series_MQTT_AT Command Manual 17 / 41
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>

SimCom SIM7800 Series Specifications

General

Brand	SimCom
Model	SIM7800 Series
Category	Control Unit
Language	English

Summary

Introduction to MQTT AT Commands

1.1 SSL Context Management for SSL/TLS MQTT

Explains AT commands for managing SSL context for MQTT.

1.2 Process of Using MQTT AT Commands

Outlines the steps for using MQTT AT commands in sequence.

MQTT AT Command Reference

2.1 SSL Context Management AT Commands

Details AT commands for configuring SSL contexts for secure MQTT connections.

2.2 MQTT Services AT Commands

Covers AT commands for starting, stopping, and managing MQTT client services.

2.3 Command Result and Unsolicited Codes

Lists all command result codes and unsolicited codes for MQTT operations.

MQTT Usage Examples

3.1 Access MQTT Server (Not SSL/TLS)

Demonstrates connecting to an MQTT server without SSL/TLS.

3.2 Connect to SSL/TLS MQTT Server (No Server Verification)

Shows connecting to SSL/TLS MQTT server without verifying the server.

3.3 Access SSL/TLS MQTT Server (Verify Server Only)

Details accessing SSL/TLS MQTT server with server verification.

3.4 Access SSL/TLS MQTT Server (Verify Server and Client)

Illustrates connecting to SSL/TLS MQTT server with both server and client verification.

3.5 Access MQTT Server without UTF8 Coding Check

Explains communication with MQTT server without UTF8 coding check.