+=item B<Type> I<Type>
+
+Specifies the "type" (data set) to use when dispatching the value to
+I<collectd>. Currently, only data sets with exactly one data source are
+supported.
+
+=item B<Instance> I<Instance>
+
+Sets the type instance to use when dispatching the value to I<collectd>. If
+unset, an empty string (no type instance) is used.
+
+=back
+
+=item E<lt>B<Host> I<Name>E<gt> blocks
+
+Host blocks are used to specify to which hosts to connect and what data to read
+from their "slaves". The string argument I<Name> is used as hostname when
+dispatching the values to I<collectd>.
+
+Within E<lt>HostE<nbsp>/E<gt> blocks, the following options are allowed:
+
+=over 4
+
+=item B<Address> I<Hostname>
+
+For Modbus/TCP, specifies the node name (the actual network address) used to
+connect to the host. This may be an IP address or a hostname. Please note that
+the used I<libmodbus> library only supports IPv4 at the moment.
+
+=item B<Port> I<Service>
+
+for Modbus/TCP, specifies the port used to connect to the host. The port can
+either be given as a number or as a service name. Please note that the
+I<Service> argument must be a string, even if ports are given in their numerical
+form. Defaults to "502".
+
+=item B<Device> I<Devicenode>
+
+For Modbus/RTU, specifies the path to the serial device being used.
+
+=item B<Baudrate> I<Baudrate>
+
+For Modbus/RTU, specifies the baud rate of the serial device.
+Note, connections currently support only 8/N/1.
+
+=item B<Interval> I<Interval>
+
+Sets the interval (in seconds) in which the values will be collected from this
+host. By default the global B<Interval> setting will be used.
+
+=item E<lt>B<Slave> I<ID>E<gt>
+
+Over each connection, multiple Modbus devices may be reached. The slave ID
+is used to specify which device should be addressed. For each device you want
+to query, one B<Slave> block must be given.
+
+Within E<lt>SlaveE<nbsp>/E<gt> blocks, the following options are allowed:
+
+=over 4
+
+=item B<Instance> I<Instance>
+
+Specify the plugin instance to use when dispatching the values to I<collectd>.
+By default "slave_I<ID>" is used.
+
+=item B<Collect> I<DataName>
+
+Specifies which data to retrieve from the device. I<DataName> must be the same
+string as the I<Name> argument passed to a B<Data> block. You can specify this
+option multiple times to collect more than one value from a slave. At least one
+B<Collect> option is mandatory.
+
+=back
+
+=back
+
+=back
+
+=head2 Plugin C<mqtt>
+
+The I<MQTT plugin> can send metrics to MQTT (B<Publish> blocks) and receive
+values from MQTT (B<Subscribe> blocks).
+
+B<Synopsis:>
+
+ <Plugin mqtt>
+ <Publish "name">
+ Host "mqtt.example.com"
+ Prefix "collectd"
+ </Publish>
+ <Subscribe "name">
+ Host "mqtt.example.com"
+ Topic "collectd/#"
+ </Subscribe>
+ </Plugin>
+
+The plugin's configuration is in B<Publish> and/or B<Subscribe> blocks,
+configuring the sending and receiving direction respectively. The plugin will
+register a write callback named C<mqtt/I<name>> where I<name> is the string
+argument given to the B<Publish> block. Both types of blocks share many but not
+all of the following options. If an option is valid in only one of the blocks,
+it will be mentioned explicitly.
+
+B<Options:>
+
+=over 4
+
+=item B<Host> I<Hostname>
+
+Hostname of the MQTT broker to connect to.
+
+=item B<Port> I<Service>
+
+Port number or service name of the MQTT broker to connect to.
+
+=item B<User> I<UserName>
+
+Username used when authenticating to the MQTT broker.
+
+=item B<Password> I<Password>
+
+Password used when authenticating to the MQTT broker.
+
+=item B<ClientId> I<ClientId>
+
+MQTT client ID to use. Defaults to the hostname used by I<collectd>.
+
+=item B<QoS> [B<0>-B<2>]
+
+Sets the I<Quality of Service>, with the values C<0>, C<1> and C<2> meaning:
+
+=over 4
+
+=item B<0>
+
+At most once