Hi
I’m trying to send SMS with the Modbus TCP server interface. When i write single holding register “Send SMS” 397 value 1, I get modbus error 3 (invalid modbus value)
Setting the text and phonenumber register 398 return error code 0, No error.
I tried installing tcpdump on the modem to check the modbus request and send it from modbus doctor (a modbus client), but it appears to send a POST request to a specific URI instead of modbus TCP.