The main differences between CM1942 and CS1942DP are

The Video output of CM1942 is HDMI, supports Video DynaSync,

The Video output of CS1942DP is DisplayPort and does not support Video DynaSync

Please refer to the attached comparison table to confirm the detailed differences. 

Besides, the most important difference is that the CM19425 supports Dual PC Mode , while the CS1942DP does not.

Dual PC Mode allows the two monitors connected to the Console port of the CM1942 can display the main screen of the computer that connected to Port 1 and Port 2 respectively, let user can operate two computers at the same time.