24 lines
1.1 KiB
Markdown
24 lines
1.1 KiB
Markdown
# RS232 gateway
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## Sending an RS232 message
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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
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`mosquitto_pub -t home/OpenMQTTGateway/commands/MQTTtoRS232 -m '{"value": "!"}'`
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It will automatically add the prefix and postfix you set in [config_RS232.h](https://github.com/1technophile/OpenMQTTGateway/blob/master/main/config_RS232.h).
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## Receiving an RS232 message
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To receive a message, subscribe to all with `mosquitto_sub -t +/# -v`
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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
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```json
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home/OpenMQTTGateway/RS232toMQTT {"value":"1"}
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```
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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
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```json
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home/OpenMQTTGateway/RStoMQTT {"value":"!:N"}
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```
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