DAQFactory communicating with other HMI's in Serial Communications Posted June 6 That would largely depend on the HMI. That particular one has 3 serial ports, so if one wasn't in use you could connect that to the PC and communicate with DAQFactory over that connection. But that is just the hardware layer. The real question is what protocol does the HMI speak? I couldn't find it on their website. If it talks Modbus, you could setup DAQFactory as a Modbus master or Modbus slave (depending on which license of DAQFactory you have) and transfer that way. That would be easiest, especially if the HMI can act as a Modbus Slave and DAQFactory can be the Modbus master.