Saw this online this morning. Don't know anything additional concerning seller or condition.

The M-600 generates both composite video and 20/60ma loop (using external loop supply). Will also convert ASCII/Baudot/SITOR/Morse and speeds.

Someone was asking about copying USCG SITOR weather broadcasts. I use a M-600 to copy/convert these broadcasts to 75baud baudot. Output baud rates are selected by dip switches inside the unit. Input speeds via keypad.

Coast Guard Weather- https://www.weather.gov/marine/uscg_broadcasts

Nick has manual here- https://www.navy-radio.com/rtty/info-tech/