1.1 KiB
RS232 gateway
Sending an RS232 message
Simply publish the message you wish to transmit, minus the prefix and postfix. For example, to send the "Turn On" signal for a Mitsubishi XD221U projector, the code is simply '!' so you would use the command
mosquitto_pub -t home/OpenMQTTGateway/commands/MQTTtoRS232 -m '{"value": "!"}'
It will automatically add the prefix and postfix you set in config_RS232.h.
Receiving an RS232 message
To receive a message, subscribe to all with mosquitto_sub -t +/# -v
and perform an action that should get a response from the device. For example, If I were to send the "Turn On" signal from earlier, I would receive back
home/OpenMQTTGateway/RS232toMQTT {"value":"1"}
Because this projector echoes back a received command to acknowledge. Some devices will send a NACK, or Negative Acknowledge, to confirm that they received your message but could not comply. That would look like
home/OpenMQTTGateway/RStoMQTT {"value":"!:N"}