I am attempting to read data from a Sigma 980 flow meter via its RS232C connection. The meter supports Modbus ASCII and I am using a Prosoft ILX34-MBS232 module to connect to it. I am unable to receive a response from the meter and I believe it has something to do with the meters DTR/DSR terminals. The prosoft module only has Tx and Rx terminals and the meter requires the DTR to be held high during transmission. How would I communicate between a Modbus device with two terminals (Rx & Tx) and one having seven? (Shield, common, DSR, RXD, DTR, TXD, 12V+)?