SimCom SIM7800 Series User Manual

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SIM7500_SIM7600_SIM7800 Series_MQTT_AT Command Manual 29 / 41
indicate the topic and payload have been transmitted completely.
Defined Values
<client_index>
A numeric parameter that identifies a client. The range of permitted
values is 0 to 1.
<topic_total_len>
The length of message topic received from MQTT server. The
range is from 1 to 1024 bytes.
<payload_total_len>
The length of message body received from MQTT server. The
range is from 1 to 10240 bytes.
<sub_topic_len>
The sub topic packet length, The sum of <sub_topic_len> is equal
to <topic_total_len>.
<sub_topic>
The sub topic content.
<sub_payload_len>
The sub message body
packet length, The sum of
<sub_payload_len> is equal to <payload_total_len>.
<sub_payload>
The sub message body content.
3 Example
Before all MQTT related operations, we should ensure the following:
a) ensure GPRS network is available:
AT+CSQ
+CSQ: 23,0
OK
AT+CREG?
+CREG: 0,1
OK
AT+CGREG?
+CGREG: 0,1
OK
b) PDP context Enable:

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.