Two way communication via RS232

I have a device running Node-Red with a RS232 port. I would like to connect it to a GPRS modem via RS232 to send telemetry data packets.

In order to do so, I need to send several AT-commands to the modem:

  1. One to transfer message payload to the modem buffer
  2. Afterwards I need to wait to "OK" response from the modem (it means the modem is ready for the communication)
  3. then I need to send the command to initiate the GPRS data transfer and if it is successful the modem returns OK.
  4. finally if OK, set the modem to idle mode until the next message payload is received.

Can you please advice how can I establish connection to RS-232 multi serial node in such talk-back communication manner with the modem?

I can set a flow with sending data to the multi serial node, but dont know how to tight the multiserial node response together...

Can you please advice any examples I can learn to configure Node-Red program?

Which node do you mean by 'multi serial node`. I can't find a node called anything like that in the node red flows page.

If you just mean the standard node-red-node-serialport then the serial-request node in that package is what you want.

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