Check the listing for details. TEKTRONIX VX4287 DIFF DI/AC A/D INPUT MODULE T40718. Condition: Used. Listed at 199.99 USD. Primary Model Number:VX4287. Reference Number:T40718. Diff Di/AC A/D Input Module. OCO Industrial: With over 20 years in the industry we have a 140,000 sq ft warehouse filled to the brim in El Paso Texas.