The 847T1-2-2-2 Programmable Oscillator Plug-in is a digitally synthesized crystal-controlled oscillator. It produces a very low distortion, highly stable sine-wave for the control of Invertron Precision AC Power Sources. The unit features botu Listener and Talker capability to provide interface via the IEEE-488 GPIB between an Invertron Power Source and a digital controller. The unit is single-phase, 45 to 999.9Hz in 1Hz steps, initilization frequency of 60Hz, and a voltage range of 270V in 0.1 volt steps..