Greetings,
The inputs to the BNC-2120 are standard BNC cables that can be purchased from most electronics stores. You will need a cable that has BNC on one end, to connect to the terminal block, and the other end must be compatible with the PeriMed Laser Doppler unit. You will have to determine what connection is needed on the PeriMed end from the manufacturer of the laser unit.
Regards,
Justin Britten
Applications Engineer
National Instruments