SARA-R4/N4 series - AT Commands Manual
UBX-17003787 - R09
24 MQTT
Page 254 of 307
Type
Syntax
Response
Example
MQTT Message
URC
+UUMQTTCM: <op_code>,<num_
unread_msgs> [Topic Len: <topic_
length>] [Topic: <topic_name>]
[Len: <msg_length> Qos: <Qos>]
Message: <message_contents>
+UUMQTTCM: 6,1 Topic: "/sensor/
heat/SD/bldg5/DelMarConfRm"
Len: 16 QoS: 0 Message: "16 bytes of
data"
24.5.3 Defined values
Parameter
Type
Description
<op_code>
Number
MQTT command request. Allowed values:
•
0: logs out/disconnects from MQTT server. Will message will not be sent
•
1: logs in/connects to MQTT server
•
2: publish a message to a specific topic to the MQTT message broker
•
3: publish a message from a file to a specific topic to the MQTT message broker
•
4: subscribe to a topic from the MQTT message broker
•
5: unsubscribe to a topic from the MQTT message broker. This should exactly
match the Topic Filter used during the Subscribe
•
6: read all unread messages received from MQTT message broker, at the terse/
verbose mode set at the time of message reception
•
7: sets the terse/verbose format for received messages (i.e. the amount of
information and headers with each received MQTT message)
•
8: ping the MQTT message broker
<QoS>
Number
Quality of service:
•
0 (default value): at most once delivery
•
1: at least once delivery
•
2: exactly once delivery
<retain>
Number
Allowed values:
•
0 (default value): the message will not be retained at the MQTT server across
disconnects from MQTT client
•
1: the message will be retained by the MQTT server across disconnects from MQTT
client (until superceded by another message)
<hex_mode>
Number
Allowed values:
•
0 (default value): ASCII input for <message_contents>
•
1: hexidecimal input for <message_contents>
<message_
contents>
String
ASCII or hexidecimal data. The starting quotation mark shall not be taken into
account like data. At the end of the byte stream, another quotation mark is provided
for user convenience and visualization purposes.
<mqtt_server>
String
IP address or URL of MQTT server
<num_unread_
msgs>
Number
Indicates the number of unread received messages.
<topic_length>
Number
Specifies the number of octets in <topic_name>
<topic_name>
String
Indicates the topic to which the given MQTT message was published
<msg_length>
Number
Specifies the number of octets in <message_contents>
<reason>
Number
Result of an MQTT subscribe request:
•
0: success
•
128: failure
<MQTT_result>
Number
Result of an MQTT command request:
•
0: fail
•
1: success
<login_result>
Number
Result of an MQTT login request.
•
0: connection accepted
•
1: the server does not support the level of the MQTT protocol requested by the Client
•
2: the client identifier is correct UTF-8 but not allowed by the Server
•
3: the network connection has been made but the MQTT service is unavailable
•
4: the data in the user name or password is malformed
•
5: the client is not authorized to connect
•
6-255: reserved for future use
