You should talk to the people who created it - they should provide technical support and will know more about their product than we will. If they don't, then find another supplier and demand your money back!
The actual communications is the easy bit - the SerialPort class
] is designed to do that - but you need to know exactly what the equipment expects to receive, and what it will transmit as a response. This varies from machine to machine; there is no one standard to cover it.