Connecting to Broker

P4M-440G can request a connection to a MQTT broker as an MQTT client.

Connect to a Broker: +MNC

Command Format
```
AT+MNC="<Broker's hostname / IP address>"  
AT+MNC="<Broker's hostname / IP address>",<Port number>  
AT+MNC="<Broker's hostname / IP address>",<Port number>,<Protocol>
```
In some cases, you can omit the port number or protocol. When omitted, the default values will be used.

Parameter Values Default Value

Port number 0 ~ 65535 1883

Protocol "tcp", "tls" "tcp"

※ Notice: If you specify the port number as 8883 and do not specify the protocol, "tls" will be used as the protocol instead of the default "tcp".
An example

at+mnc="203.0.113.0"
OK

An example: Specifying a port number

at+mnc="203.0.113.0",8883
OK

An example: Specifying both a port number and a protocol with a hostname

at+mnc="example.com",8884,"tls"
OK

Check Connection Status: +MQNS

Command Format

AT+MQNS

Response Code

Code	Description
0	Not conencted
1	Hostname lookup is in progress
2	TCP/TLS connection is in progress
3	TCP/TLS connected + MQTT connecton is in progress
4	MQTT Connected
5	MQTT Connected + Wait for a response (PUBACK / SUBACK / UNSUBACK)

An example

at+mnc="203.0.113.0"
OK
at+mqns
+MQNS:4
OK

Disconnect from a Broker: +MND

Command Format

AT+MND

An example

at+mqns
+MQNS:4
OK
at+mnd
OK
at+mqns
+MQNS:0
OK