The Tektronix 1910 is designed for performance testing of NTSC video systems and equipment. It is especially suited where high accuracy and stability are required. It is also a VITS inserter (internal and external) with a full complement of signals that allow testing in studio, transmitter, production or research environments. Four external VITS inputs permit insertion of signals such as videotext, closed captioning, source ID, and other similar sources. These four inputs may be converted to four pulse outputs for use in a production environment. GPIB and RS-232 interfaces.