These Thermo Scientific interface cables are used to connect the Thermo Scientific ThermoFlex 900, 1400, & 2500 via RS232/RS485 serial communication interfaces to a desktop or laptop computer. The NC serial communications protocol is based on a master-slave model. The master is a host computer, while the slave is the chiller's controller. Only the master can initiate a communications transaction (half-duplex). The slave ends the transaction by responding to the master’s query. The protocol uses RS-232/RS-485 serial interface with the default parameters: 9600 baud, 8 data bits, 1 stop bit, and no parity. RS-485 offers a slave address selection, default parameter: 1. The unit can be controlled through your computer’s serial port by using the unit's standard female 9-pin connection. (RS-232/RS-485 serial interface are optional accessories in some units and are sold separately)