AMCM-860 is a frequency-agile analog audio/video modulator available in NTSC channels 2-135 (54-860 MHz). Models are available in both stereo and mono audio inputs. This 4th generation of AMCM-860 is equipped with the CALMTones feature, utilizing Audio AGC (Automatic GainControl) circuitry that eliminates variations in loudness level that may be present among various program sources.