• Introduction
  • Features
  • Hardware Specifications
  • Dimensions
  • Layout
  • Interfaces
  • Application
• Basic Usage
  • Management Software
    • Connection with a PC
    • Initial Setup and Certificates
    • Firmware Upgrade
  • Reset
• MQTT Usage
  • Preparation
    • File System
    • AT Commands
    • Connecting Devices
  • MQTT Settings
    • Topic and Message Buffer
    • Timeout
    • Connection Flags
    • Connection Payload
    • QoS
  • Connecting to Broker
  • SUBSCRIBE
  • PUBLISH
  • Reading Messages
  • Etc.
    • Reading the Client ID
    • Setting Short Response
• Advanced
  • ATC & MQTT Settings
  • Activating PHPoC Engine
  • Advanced AT Commands

SUBSCRIBE

P4M-440G, as an MQTT client, can request to subscribe to a specific topic on the MQTT broker or request to unsubscribe from topics it has subscribed to.

SUBSCRIBE Request: +MBS

• Command Format

AT+MBS="<Topic>"
AT+MBS=<An ID of a Topic Buffer>

• An example

at+mbs="test/test_topic"
OK
at+mqns
+MQNS:4
OK

• An example: Using a tpoic buffer

at+mbt=0,"test/test_topic"
OK
at+mbs=0
OK
at+mqns
+MQNS:4
OK

UNSUBSCRIBE Request: +MBU

• Command Format

AT+MBU="<Topic>"
AT+MBU=<An ID of a Topic Buffer>

• An example

at+mbu="test/test_topic"
OK
at+mqns
+MQNS:4
OK

• An example: Using a topic buffer

at+mbt=0,"test/test_topic"
OK
at+mbu=0
OK
at+mqns
+MQNS:4
OK