Complex sentence: The third one in the series is the "RS690M" for mobile platform, named M690 with the fourth one is the "RS690MC", a simplified version of M690 and without TMDS support, called M690V.
Split into simpler sentences: The third one in the series is the "RS690M" for mobile platform, named M690. The fourth one is the "RS690MC", a simplified version of M690 and without TMDS support, called M690V.